MEMBERSHIP INTEREST PURCHASE AGREEMENT

<PAGE>

EXHIBIT 2.1

MEMBERSHIP INTEREST PURCHASE AGREEMENT

Among:

GLOBAL PATENT HOLDINGS, LLC,

a Delaware limited liability company,

ACACIA RESEARCH CORPORATION,

a Delaware corporation

and

ACACIA GLOBAL ACQUISITION CORPORATION,

a Delaware corporation

----------------

Dated as of January 28, 2005

----------------

<PAGE>

TABLE OF CONTENTS

PAGE

----

1. Sale and Purchase of LLC Interests; Related Transactions..................1

1.1. Sale and Purchase of LLC Interests.................................1

1.2. Purchase Price.....................................................1

1.3. Closing............................................................1

2. Representations and Warranties of Seller..................................2

2.1. Due Organization; No Subsidiaries..................................2

2.2. Organizational Documents; Records..................................3

2.3. Capitalization.....................................................3

2.4. Financial Statements...............................................4

2.5. Absence of Changes.................................................4

2.6. Title to Assets....................................................5

2.7. Intellectual Property Rights.......................................5

2.8. Contracts; Consents................................................6

2.9. No Undisclosed Liabilities.........................................7

2.10. Compliance with Legal Requirements.................................8

2.11. Governmental Authorizations........................................8

2.12. Tax Matters........................................................8

2.13. Labor Matters; Benefit Plans.......................................9

2.14. Intellectual Property Disclosures..................................9

2.15. Related Party Transactions.........................................9

2.16. Proceeds; Orders..................................................10

2.17. Authority; Binding Nature of Agreements...........................10

2.18. Non-Contravention; Consents.......................................11

2.19. Brokers...........................................................11

2.20. Investment Company Act............................................11

2.21. Investment Representations........................................12

2.22. Solvency..........................................................13

2.23. Exclusive Representations and Warranties..........................13

3. Representations and Warranties of Purchaser and Acacia...................13

i

<PAGE>

3.1. Due Organization; Good Standing...................................14

3.2. Authority; Binding Nature Of Agreements...........................14

3.3. No Default, Violation or Consent..................................14

3.4. No Proceedings....................................................15

3.5. SEC Filings; Purchaser Financial Statements.......................15

3.6. No Material Adverse Effect........................................15

3.7. Brokers...........................................................16

3.8. Purchase Shares...................................................16

3.9. No Representations................................................16

4. Closing Deliverables.....................................................16

4.1. Agreements and Documents of Seller................................16

4.2. Agreements and Documents of the Purchaser and Acacia..............17

5. Post-Closing Covenants Of The Parties....................................18

5.1. Filings And Consents..............................................18

5.2. Tax Allocation....................................................19

6. Indemnification..........................................................19

6.1. Survival of Seller Representations................................19

6.2. Indemnification By Seller.........................................19

6.3. Threshold; Ceiling; Limits........................................20

6.4. Exercise Of Remedies By Seller Indemnitees Other Than Purchaser...21

6.5. Survival of Purchaser and Acacia Representations..................21

6.6. Indemnification By Acacia.........................................21

6.7. Notice and Defense of Third Party Claims..........................22

6.8. Losses Net of Insurance, Recoveries, Etc..........................23

6.9. Sole and Exclusive Remedies.......................................24

7. Miscellaneous............................................................24

7.1. Further Assurances................................................24

7.2. Fees And Expenses.................................................24

7.3. Notices...........................................................25

7.4. Time Of The Essence...............................................27

7.5. Headings..........................................................27

ii

<PAGE>

7.6. Counterparts......................................................27

7.7. Governing Law.....................................................27

7.8. Successors and Assigns............................................27

7.9. Waiver............................................................27

7.10. Amendments........................................................28

7.11. Severability......................................................28

7.12. Parties In Interest...............................................28

7.13. Limitation of Individual Liability................................28

7.14. Entire Agreement..................................................28

7.15. Construction......................................................29

iii

<PAGE>

MEMBERSHIP INTEREST PURCHASE AGREEMENT

This Membership Interest Purchase Agreement is entered into as of

January 28, 2005, by and among Global Patent Holdings, LLC, a Delaware limited

liability company ("Seller"), Acacia Research Corporation, a Delaware

corporation ("Acacia"), and Acacia Global Acquisition Corporation, a Delaware

corporation and a wholly-owned subsidiary of Acacia ("Purchaser"). Certain

capitalized terms used in this Agreement are defined in Exhibit A.

RECITALS

A. Seller owns all of the issued and outstanding membership interests

of the Acquired Companies (collectively, the "LLC Interests"), which constitute

all of the outstanding equity and other interests of the Acquired Companies.

B. Seller wishes to sell all of the LLC Interests to the Purchaser, and

the Purchaser desires to purchase all of the LLC Interests from Seller, on the

terms and subject to the conditions set forth in this Agreement.

AGREEMENT

The Purchaser, Acacia and Seller, intending to be legally bound, agree

as follows:

1. SALE AND PURCHASE OF LLC INTERESTS; RELATED TRANSACTIONS

1.1. SALE AND PURCHASE OF LLC INTERESTS. At the Closing, Seller shall

sell, assign, transfer and deliver the LLC Interests, free and clear of all

Encumbrances as of the date hereof, to the Purchaser, and the Purchaser shall,

and Acacia shall cause the Purchaser to, purchase, assume and accept the LLC

Interests from Seller, on the terms and subject to the conditions set forth in

this Agreement.

1.2. PURCHASE PRICE.

(a) The aggregate purchase price payable by the Purchaser for

the LLC Interests (the "Purchase Price") shall be payable in cash and ACTG Stock

as follows:

(i) cash in the amount of Three Million Dollars

($3,000,000) (the "Cash Consideration"); and

(ii) 3,938,832 shares of ACTG Stock, which shall be

issued to Seller or its members at the Closing (the "Purchase Shares").

1.3. CLOSING.

(a) The closing of the purchase and sale of the LLC Interests

hereunder (the "Closing") shall take place on the date this Agreement is signed

at such place and time as the Purchaser and Seller may jointly designate).

"Closing Date" shall mean the date as of which the Closing actually takes place,

and "Effective Time" shall mean the time as of which the Closing actually takes

place.

1

<PAGE>

(b) At the Closing:

(i) the Purchaser shall pay to Seller by wire

transfer the Cash Consideration and shall issue and deliver to Seller (or to the

members of Seller, pro rata, as directed by Seller) certificates representing

the Purchase Shares; and

(ii) the parties shall deliver each of the closing

deliverables set forth in Section 4.

2. REPRESENTATIONS AND WARRANTIES OF SELLER

Seller represents and warrants to the Purchaser, as of the Closing

Date, as follows:

2.1. DUE ORGANIZATION; NO SUBSIDIARIES.

(a) Seller and each of the Acquired Companies are limited

liability companies duly organized, validly existing and in good standing under

the laws of the state of their respective organization, and each of these

limited liability companies has all necessary power and authority:

(i) to conduct its business in the manner in which

its business is currently being conducted;

(ii) to own and use its assets in the manner in which

its assets are currently owned and used; and

(iii) to perform its obligations under all its

Contracts.

(b) Seller and each of the Acquired Companies are in good

standing as a foreign limited liability company in each of the jurisdictions

identified in Part 2.1(b) of the Disclosure Schedule.

(c) Part 2.1(c) of the Disclosure Schedule accurately sets

forth (i) the names of the managers and members of each of Seller and the

Acquired Companies and (ii) the names of the officers of each of Seller and the

Acquired Companies.

(d) None of Seller, the Acquired Companies nor any of their

respective managers or members, has ever approved, or commenced any proceeding

or made any election contemplating, the dissolution, liquidation, sale or other

disposition of Seller, any of the Acquired Companies or the winding up or

cessation of Seller's or any of the Acquired Companies' respective business or

affairs.

2

<PAGE>

(e) Except as set forth in Part 2.1(e) of the Disclosure

Schedule, each of the Acquired Companies has no subsidiaries, and has never

owned, beneficially or otherwise, any shares or other securities of, or any

direct or indirect ownership interest of any nature in, any Entity. Seller

currently has no Subsidiaries other than the Acquired Companies.

2.2. ORGANIZATIONAL DOCUMENTS; RECORDS.

(a) Seller has delivered to the Purchaser accurate and

complete copies of:

(i) Organizational Documents for each of Seller and

the Acquired Companies, including all amendments thereto;

(ii) the membership interest register or other

membership interest records of each of Seller and the Acquired Companies; and

(iii) the minutes and other records of the meetings

and other proceedings (including any actions taken by written consent or

otherwise without a meeting) of the managers of each of the Acquired Companies

and of the members of each of Seller and the Acquired Companies.

(b) The Acquired Companies have never engaged in any business

other than the purchasing and licensing of the Intellectual Property Rights and

enforcement of rights related to the Intellectual Property Rights and related

activities.

2.3. CAPITALIZATION.

(a) The authorized equity of each of the Acquired Companies

consists of membership interests represented by the LLC Interests specified in

Part 2.3(a) of the Disclosure Schedule, all of which are outstanding and owned,

beneficially and of record, by Seller.

(b) Seller has, and the Purchaser will acquire at the Closing,

good, valid and marketable title to all of the LLC Interests free and clear of

any Encumbrances.

(c) All of the LLC Interests (i) have been duly authorized and

validly issued, (ii) are fully paid and non-assessable, and (iii) have been

issued in full compliance with all applicable securities laws and other

applicable Legal Requirements.

(d) There is no:

(i) outstanding subscription, option, call, warrant

or right (whether or not currently exercisable) to acquire any equity interest

in, or other security of, any of the Acquired Companies;

(ii) outstanding security, instrument or obligation

that is or may become convertible into or exchangeable for any equity interest

in, or other security of, any of the Acquired Companies;

3

<PAGE>

(iii) Contract under which any of the Acquired

Companies is or may become obligated to sell or otherwise issue any equity

interest or other security; or

(iv) any condition or circumstance that may directly

or indirectly give rise to or provide a basis for the assertion of a claim by

any Person to the effect that such Person is entitled to acquire or receive any

equity interest in, or other security of, any of the Acquired Companies.

2.4. FINANCIAL STATEMENTS

(a) Seller has delivered to Buyer the unaudited consolidated

balance sheets of Seller and each Acquired Company, as applicable, as at

December 31 of each of the fiscal years 1999 through 2004 ("Balance Sheets"),

and the related unaudited consolidated statements of income for each of the

fiscal years then ended (the "Financial Statements"). The Financial Statements

fairly present in all material respects the financial condition and the results

of operations of each of Seller and the Acquired Companies on a consolidated

basis, as applicable, as at the respective dates of and for the periods referred

to in such Financial Statements. The Financial Statements reflect in all

material respects the consistent application of accounting principles throughout

the periods involved. The Financial Statements have been and will be prepared

from and are in accordance with, in all material respects, accounting Records of

Seller and each of the Acquired Companies.

(b) Each of the Seller's and the Acquired Companies' books of

account and other financial Records, all of which have been made available to

the Purchaser, are complete and correct in all material respects and represent

in all material respects actual, bona fide transactions and have been maintained

in all material respects in accordance with sound business practices, including

the maintenance of an adequate system of internal controls. At the Closing, all

of books and Records of the Acquired Companies will be in the possession of the

Acquired Companies.

2.5. ABSENCE OF CHANGES.

Except as provided in the Transactional Agreements, since December 31,

2004:

(a) None of the Acquired Companies has made any promises to

any Persons with regard to future employment or engagement;

(b) Except as specified in Part 2.5(b) of the Disclosure

Schedule, none of the Acquired Companies has entered into, nor have any of the

assets owned or used by the Acquired Companies become bound by, any material

Contract;

(c) Except as specified in Part 2.5(c) of the Disclosure

Schedule, no material Contract by which the Acquired Companies or any of the

assets owned or used by the Acquired Companies is or was bound, or under which

the Acquired Companies has or had any rights or interest, has been amended or

terminated;

4

<PAGE>

(d) None of the Acquired Companies has changed any of its

methods of accounting or accounting practices in any respect;

(e) None of the Acquired Companies has entered into any

transaction or taken any other action outside the Ordinary Course of Business

except for the Transactions;

(f) None of the Acquired Companies has agreed, committed or

offered (in writing or otherwise), and has not attempted, to take any of the

actions referred to in clauses "(a)" through "(e)" above; and

(g) Except as specified in Part 2.5, including Part 2.5(g), of

the Disclosure Schedule, each of the Acquired Companies has (i) operated its

business in the Ordinary Course of Business and consistent with past practice

and (ii) preserved intact its relationships with its customers, licensees,

licensors, suppliers, providers, payors and other Persons with which it has

significant business relationships.

2.6. TITLE TO ASSETS.

(a) Except as provided in Part 2.6(b) of the Disclosure

Schedule, each of the Acquired Companies owns, and has good, valid and

marketable title to, all assets purported to be owned by it, free and clear of

Encumbrances, including without limitation: (i) all Intellectual Property Rights

identified or required to be identified in Parts 2.7(a)(i) of the Disclosure

Schedule and (ii) all other assets reflected in the books and records of the

Acquired Companies as being owned by such Acquired Companies. Additionally, to

Seller's Knowledge, except as provided in Part 2.8(b) of the Disclosure

Schedule, each of the Acquired Companies has a valid right to license and

enforce all Intellectual Property Rights identified in Part 2.7(a)(ii) and in

the IP Contracts listed in Part 2.7(a)(iv) of the Disclosure Schedule free and

clear of all Encumbrances.

(b) Except as set forth in Part 2.6(b) of the Disclosure

Schedule, all of such assets are owned by the Acquired Companies free and clear

of any Encumbrances as of the date hereof.

2.7. INTELLECTUAL PROPERTY RIGHTS.

(a)

(i) Part 2.7(a)(i) of the Disclosure Schedule sets

forth a complete list of each Patent in which any of the Acquired Companies has

an ownership interest.

(ii) Part 2.7(a)(ii) of the Disclosure Schedule sets

forth a complete list of each Patent in which a third party has an ownership

interest and which any of the Acquired Companies has license and/or enforcement

rights.

(iii) Part 2.7(a)(iii) of the Disclosure Schedule

identifies, and Seller has delivered to Purchaser, accurate and complete copies

of, each of the IP Contracts under which any of the Acquired Companies has any

ongoing royalty or payment obligations, and to Seller's Knowledge, there are no

outstanding or threatened disputes, disagreements, claims or Proceedings with

respect to any such IP Contracts, except as described in Part 2.8(b) or any

other part of the Disclosure Schedule.

5

<PAGE>

(iv) To the Seller's Knowledge, any IP Contract,

pursuant to which any Acquired Company, as owner or licensee of any Patent, has

granted to any third party any right (whether or not currently exercisable) to

use, license or otherwise exploit any material Intellectual Property Rights, has

been identified in Part 2.7(a)(iv) of the Disclosure Schedule. Additionally, to

the Seller's Knowledge, Seller has provided Purchaser with access to all written

information in its possession which identifies any Person who has a right

(whether or not currently exercisable) to use, license or otherwise exploit any

Intellectual Property Rights.

(v) Except as set forth in Part 2.7(a)(v) of the

Disclosure Schedule, regarding the Patents identified in Parts 2.7(a)(i) or

(ii), to the Seller's Knowledge, (i) no such Patents have expired due to failure

to make a required maintenance fee, and (ii) such Patents are not now involved

in any interference, reissue, reexamination or opposition proceeding.

(vi) To Seller's Knowledge, as of the Effective Time,

there are no divisions, continuations or continuations-in-part to any of the

Patents listed in Parts 2.7(a)(i) or (ii).

(b) None of the Acquired Companies have (i) licensed any of

the Intellectual Property Rights listed in Parts 2.7(a)(i) or 2.7(a)(ii) to any

other Person on an exclusive basis, or (ii) except as may otherwise be provided

in any of the Contracts included in the Disclosure Schedule, (x) entered into

any Contract under which any other Person has the right to distribute, license

or sublicense any of the Intellectual Property Rights listed in Parts 2.7(a)(i)

or 2.7(a)(ii), or (y) entered into any covenant not to compete or other Contract

limiting the ability of any of the Acquired Companies to fully exploit any of

the Intellectual Property Rights listed in Parts 2.7(a)(i) or 2.7(a)(ii) or to

transact business in any market or geographical area or with any other Person.

(c) To Seller's Knowledge, no current or former employee,

officer, manager, member, consultant or independent contractor of Seller or any

of the Acquired Companies has any right, claim or interest in or with respect to

any Intellectual Property.

2.8. CONTRACTS; CONSENTS.

(a) Except as may otherwise be provided and identified in any

of the Contracts listed in Part 2.8(a) of the Disclosure Schedule, no Contract

contains a "most favored nations" provision. To the Knowledge of Seller, Seller

has delivered to the Purchaser accurate and complete copies of each Contract

identified in Part 2.8(a) of the Disclosure Schedule. Subject to Part 2.8(b) of

the Disclosure Schedule, each such Contract, assuming the due authorization,

execution and delivery thereof by each of the other parties thereto, is valid

and in full force and effect, and is enforceable by the Acquired Companies in

accordance with its terms subject to (i) laws of general application relating to

bankruptcy, insolvency, reorganization, moratorium and the relief of debtors,

and (ii) rules of law governing specific performance, injunctive relief or other

equitable remedies.

6

<PAGE>

(b) Except as set forth in Part 2.8(b) of the Disclosure

Schedule, to the Knowledge of Seller:

(i) no Acquired Company has materially violated,

Breached, declared or committed any material default under any IP Contract or

material Company Contract, and, to the Knowledge of Seller, no other Person has

materially violated, Breached, declared or committed any material default under

any IP Contract or Company Contract;

(ii) no event has occurred, and no circumstance or

condition exists, that (with or without notice or lapse of time) can reasonably

be expected to, (A) result in a material violation or material Breach of any of

the provisions of any IP Contract or Company Contract, (B) give any Person the

right to declare a material default or exercise any remedy under any IP Contract

or Company Contract, (C) give any Person the right to accelerate the maturity or

performance of any IP Contract or Company Contract, or (D) give any Person the

right to cancel, terminate or materially modify any IP Contract or Company

Contract; and

(iii) none of the Acquired Companies has waived any

of its material rights under any IP Contract or Company Contract, except as

disclosed in the Disclosure Schedule.

(c) Part 2.8(c) of the Disclosure Schedule identifies each

Consent required to be obtained by the Seller and each notice required to be

made by the Seller or the Acquired Companies to any Person for (i) the transfer

of the LLC Interests to the Purchaser at the Closing, (ii) the avoidance, upon

transfer of the LLC Interests to the Purchaser at the Closing, of any of the

circumstances set forth in Section 2.8(b)(ii)(A)-(D) above, and (iii) the

execution and delivery of any of the Transactional Agreements or the

consummation or performance of any of the Transactions.

2.9. NO UNDISCLOSED LIABILITIES. Each of the Acquired Companies has no

Liabilities required to be reflected on a balance sheet prepared in accordance

with GAAP except (i) for Liabilities identified as such in the "liabilities"

column of the consolidated Financial Statements dated as of December 31, 2004,

(ii) for trade payables incurred in the Ordinary Course of Business, (iii) for

any of the Acquired Companies' obligations under the IP Contracts or Company

Contracts listed in Part 2.8(a) of the Disclosure Schedule and (iv) as set forth

on Part 2.9 of the Disclosure Schedule. The Acquired Companies have no operating

leases, except as listed, if any, in the Disclosure Schedule.

7

<PAGE>

2.10. COMPLIANCE WITH LEGAL REQUIREMENTS. To the Knowledge of Seller,

except for qualification, authorization, registration or licensing to do

business as a foreign limited liability company and except in such instances

where it would not be reasonably likely to have a Material Adverse Effect, each

of the Acquired Companies has conducted its business in compliance with all, and

is not in violation of, any applicable Legal Requirements. None of Seller or any

of the Acquired Companies has received any written notification of any asserted

present or past failure by any of the Acquired Companies to comply with any

applicable Legal Requirements or Order.

2.11. GOVERNMENTAL AUTHORIZATIONS. To Knowledge of Seller, no

Governmental Authorizations are necessary or required by applicable law in

connection with the execution, delivery and performance of the Transaction

Agreements or the Transactions by Seller and Seller's members or in connection

with the operation of the Acquired Companies' respective businesses.

2.12. TAX MATTERS.

(a) Seller and the Acquired Companies have filed or caused to

be filed on a timely basis all Tax Returns required to be filed by them pursuant

to applicable Legal Requirements and that relate to the business of the Acquired

Companies. All Tax Returns filed by Seller and each of the Acquired Companies

that relate to the business of the Acquired Companies are true, correct and

complete in all material respects. Each of Seller and the Acquired Companies has

paid, or made provision for the payment of, all Taxes that relate to the

business of the Acquired Companies prior to the Closing Date and that are due

for all periods covered by such Tax Returns or otherwise due prior to the

Closing Date, or pursuant to any assessment received by Seller or the Acquired

Companies prior to the Closing Date. Neither Seller nor any of the Acquired

Companies is the beneficiary of any extension of time within which to file any

Tax Return. No claim has ever been made by any taxing authority in a writing

received by Seller or any of the Acquired Companies in a jurisdiction where

Seller or any of the Acquired Companies does not file Tax Returns that Seller or

any of the Acquired Companies is or may be subject to taxation by that

jurisdiction on income attributable to the business of the Acquired Companies.

As of the date hereof, there are no Encumbrances on any of the Acquired

Companies' assets or properties that arose in connection with any failure (or

alleged failure) to pay any Tax.

(b) Seller and each of the Acquired Companies has delivered or

made available to the Purchaser copies of all Tax Returns of Seller and the

Acquired Companies filed since their respective dates of formation. There is no

dispute or claim concerning any Taxes of Seller or any of the Acquired Companies

relating to the business of the Acquired Companies raised by any taxing

authority in a writing received by Seller or any of the Acquired Companies.

There has not been received by Seller or any of the Acquired Companies in

writing a proposed Tax assessment or deficiency against Seller or any of the

Acquired Companies relating to the business of the Acquired Companies.

(c) All Taxes relating to the business of the Acquired

Companies that Seller and each of the Acquired Companies is or was required by

Legal Requirements to withhold, deduct or collect have been duly withheld,

deducted and collected and, to the extent required, have been paid to the proper

Governmental Body or other Person.

8

<PAGE>

(d) Except as set forth in Part 2.12 of the Disclosure

Schedule, there is not currently in effect with respect to any of the Acquired

Companies any tax sharing agreement, tax allocation agreement, tax indemnity

obligation or similar agreement, arrangement or understanding or practice with

respect to Taxes that will require any payment by any of the Acquired Companies

after the Closing Date.

(e) Since the date of each of the Acquired Companies'

formation, each of the Acquired Companies has qualified for and has taken

properly all necessary steps to be treated as a disregarded entity for federal

and all applicable state income tax purposes, as provided for by Treasury

Regulations Sections 301.7701-1, et seq., and none of Seller or the Acquired

Companies has taken a position inconsistent with such treatment.

2.13. LABOR MATTERS; BENEFIT PLANS.

(a) Except as set forth in Part 2.13(a) of the Disclosure

Schedule, none of the Acquired Companies has ever had any employees or

independent contractors.

(b) Since the effective date of ERISA, there have not been,

nor are there now existing, any events or conditions which would permit any Plan

to be terminated by the PBGC under circumstances which would cause Seller or any

of the Acquired Companies to incur a Liability under Title IV of ERISA. Since

the effective date of ERISA, no Reportable Event has occurred with respect to

any Plan and no Plan has been terminated in whole or in part. No withdrawals

from any Plans have occurred which could subject the Seller or any of the

Acquired Companies to any liability.

2.14. INTELLECTUAL PROPERTY DISCLOSURES. Seller has made available to

Purchaser in all material respects all information and assistance that the

Purchaser has requested regarding the Intellectual Property Rights.

2.15. RELATED PARTY TRANSACTIONS. Except as set forth in Part 2.16 of

the Disclosure Schedule and other than its ownership of the LLC Interests or

membership interests of the Seller or as contemplated by the Transactional

Agreements, (a) to Seller's Knowledge no Related Party has any direct or

indirect interest of any nature in or to the Acquired Companies or any of the

assets of the Acquired Companies, including the Intellectual Property Rights,

(b) none of the Acquired Companies are indebted to any Related Party, (c) no

Related Party has entered into, or has any direct or indirect financial interest

in, any IP Contract or Company Contract, or any transaction or business dealing

of any nature involving the Acquired Companies or the Intellectual Property

Rights; (d) no Related Party is competing, directly or indirectly, with the

Acquired Companies; and (e) no Related Party has any claim or right against any

of the Acquired Companies (including rights to receive compensation for services

performed as an employee or Independent Contractor of Seller).

9

<PAGE>

2.16. PROCEEDS; ORDERS. Except as set forth in Part 2.16 of the

Disclosure Schedule, to Seller's Knowledge there is no pending Proceeding, and

the Seller has not received notice of any threat made by any Person to commence

any Proceeding (a) that involves the Seller, the Intellectual Property Rights or

any of the Acquired Companies or that otherwise relates to or might have a

Material Adverse Effect on the Intellectual Property Rights or any of the

Acquired Companies (whether or not any of the Acquired Companies are named as a

party thereto) or (b) that may have the effect of preventing, materially

delaying, making illegal or otherwise materially interfering with, any of the

Transactions. To the Seller's Knowledge, there is no Order to which any of the

Acquired Companies or any of the material assets owned or used by any of the

Acquired Companies (including the Intellectual Property Rights and the IP

Contracts), is subject. To the Seller's Knowledge, no employee or independent

contractor of Seller is subject to any Order that prohibits such Person from

engaging in or continuing any conduct, activity or practice relating to any of

the Acquired Companies or their Intellectual Property Rights.

2.17. AUTHORITY; BINDING NATURE OF AGREEMENTS. Seller has the absolute

and unrestricted right, power and authority to enter into and to perform its

obligations under the Transactional Agreements. The execution, delivery and

performance by Seller of the Transactional Agreements and the Transactions have

been duly authorized by all necessary action on the part of Seller and its

members, managers and officers. The Transactions have been duly authorized by

all necessary action on the part of Seller and its members, managers and

officers. This Agreement, assuming the due authorization, execution and delivery

thereof by each of the other parties thereto, constitutes the legal, valid and

binding obligation of Seller, enforceable against Seller in accordance with its

terms, and upon the execution of each of the other Transactional Agreements at

the Closing, each of such other Transactional Agreements to which Seller is a

party will, assuming the due authorization, execution and delivery thereof by

each of the other parties thereto, constitute the legal, valid and binding

obligation of Seller, enforceable against Seller in accordance with its terms

subject to (i) laws of general application relating to bankruptcy, insolvency,

reorganization, moratorium and the relief of debtors, and (ii) rules of law

governing specific performance, injunctive relief or other equitable remedies.

10

<PAGE>

2.18. NON-CONTRAVENTION; CONSENTS.

Except as would not be reasonably likely to have a Material Adverse

Effect or as disclosed in Part 2.8 of the Disclosure Schedule, neither the

execution and delivery of any of the Transactional Agreements, nor the

consummation or performance of any of the Transactions, will directly or

indirectly (with or without notice or lapse of time):

(a) contravene, conflict with or result in a violation of (i)

any of the provisions of Seller's or any of Acquired Companies' Organizational

Documents, or (ii) any resolution adopted by Seller's managers or members;

(b) contravene, conflict with or result in a violation of, or

give any Governmental Body or other Person the right to challenge any of the

Transactions or to exercise any remedy or obtain any relief under, any Legal

Requirement or any Order to which Seller, or any of Acquired Companies or any of

their respective members, or any of the assets owned or used by any of the

Acquired Companies, is subject;

(c) contravene, conflict with or result in a violation of any

of the terms or requirements of, or give any Governmental Body the right to

revoke, withdraw, suspend, cancel, terminate or modify, any Governmental

Authorization that is held by any of the Acquired Companies or that otherwise

relates to any of the Acquired Companies' business or to any of the assets owned

or used by any of the Acquired Companies;

(d) contravene, conflict with or result in a violation or

Breach of, or result in a default under, any provision of any IP Contract or

Company Contract;

(e) give any Person a right to (i) declare a default or

exercise any remedy under any IP Contract or Company Contract, (ii) accelerate

the maturity or performance of any IP Contract or Company Contract, or (iii)

cancel, terminate or modify any IP Contract or Company Contract; or

(f) result in the imposition or creation of any Encumbrance

upon or with respect to any asset owned or used by any of the Acquired

Companies.

2.19. BROKERS. None of Seller, any of the Acquired Companies or any of

their respective members has agreed or become obligated to pay, or has taken any

action that might result in any Person claiming to be entitled to receive, any

brokerage commission, finder's fee or similar commission or fee in connection

with any of the Transactions.

2.20. INVESTMENT COMPANY ACT. Seller is not an "investment company" or

a company "controlled" by an "investment company," within the meaning of the

Investment Company Act of 1940, as amended

11

<PAGE>

2.21. INVESTMENT REPRESENTATIONS.

(a) Seller (and to Seller's Knowledge, its members)

understands that the Purchase Shares are being offered and sold pursuant to a

private placement exemption from registration contained in the Securities Act of

1933, as amended (the "Securities Act") based in part upon Seller's

representations contained in this Agreement and upon the representations of

Seller's members contained in the Investment Representation Letter.

(b) Seller (and to Seller's Knowledge, its members) have

substantial experience in evaluating and investing in private placement

transactions of securities in companies similar to Acacia so that they are

capable of evaluating the merits and risks of their investment in Acacia and

have the capacity to protect their own interests. Seller (and to Seller's

Knowledge, its members) must bear the economic risk of this investment

indefinitely unless the Purchase Shares are registered pursuant to the

Securities Act, or an exemption from registration is available. Seller (and to

Seller's Knowledge, its members) also understand that there is no assurance that

any exemption from registration under the Securities Act will be available and

that, even if available, such exemption may not allow Seller or its members to

transfer all or any portion of the Purchase Shares under the circumstances, in

the amounts or at the times Seller and its members might propose.

(c) Seller is acquiring the Purchase Shares for its own

account for investment only, and not with a view towards their distribution.

(d) Seller represents that by reason of its, or of its

management's, business or financial experience, Seller has the capacity to

protect their own interests in connection with the transactions contemplated in

the Agreement. Further, Seller is aware of no publication of any advertisement

in connection with the transactions contemplated in the Agreement.

(e) Seller is an accredited investor within the meaning of

Rule 501(a) of Regulation D under the Securities Act.

(f) Seller has had an opportunity to discuss Acacia's

business, management and financial affairs with directors, officers and

management of Acacia and have had the opportunity to review Acacia's operations

and facilities. Seller has also had the opportunity to ask questions of and

receive answers from Acacia and its management regarding the terms and

conditions of this investment.

(g) Seller acknowledges and agrees that the Purchase Shares

must be held indefinitely unless they are subsequently registered under the

Securities Act or an exemption from such registration is available. Seller and

its members have been advised or are aware of the provisions of Rule 144

promulgated under the Securities Act as in effect on the date hereof, which

permits limited resale of shares purchased in a private placement subject to the

satisfaction of certain conditions, including, among other things: the

availability of certain current public information about Acacia, the resale

occurring following the required holding period under Rule 144 and the number of

shares being sold during any three-month period not exceeding specified

limitations.

(h) The office of Seller in which its investment decision was

made is located at the address or addresses of Seller set forth in Part 2.23(h)

of the Disclosure Schedule. Seller or to Seller's knowledge its members are

United States persons (as defined by Section 7701(a)(30) of the Internal Revenue

Code of 1986, as amended).

(i) Seller acknowledges and agrees that the Purchase Shares

are subject to restrictions on transfer as set forth in the applicable

securities laws.

12

<PAGE>

(j) All certificates representing the Purchase Shares shall

have endorsed thereon legends in substantially the following forms (in addition

to any other legend which may be required by other agreements between the

parties hereto):

(i) "THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE

NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "ACT"),

AND MAY NOT BE OFFERED, SOLD OR OTHERWISE TRANSFERRED, ASSIGNED, PLEDGED OR

HYPOTHECATED UNLESS AND UNTIL REGISTERED UNDER THE ACT OR UNLESS THE COMPANY HAS

RECEIVED AN OPINION OF COUNSEL SATISFACTORY TO THE COMPANY AND ITS COUNSEL THAT

SUCH REGISTRATION IS NOT REQUIRED."

(ii) Any legend required by appropriate blue sky

officials.

2.22. SOLVENCY. Immediately after the consummation of the Transactions,

(a) the fair value of the assets of Seller will exceed its debts and

Liabilities, subordinated, contingent or otherwise, (b) the present fair

saleable value of the property of Seller will be greater than the amount that

will be required to pay the probable obligations of its debts and other

Liabilities, subordinated, contingent or otherwise, as such debts and other

Liabilities become absolute and matured and (c) Seller will be able to pay its

debts and Liabilities, subordinated, contingent or otherwise, as such debts and

Liabilities become absolute and matured.

2.23. EXCLUSIVE REPRESENTATIONS AND WARRANTIES. Other than the

representations and warranties set forth in this Article 2, Seller is not making

any other representation or warranty, express or implied. Seller has provided

the Purchaser and the Purchaser's Representatives with full and complete access

to all records and other documents and data relating to the Acquired Companies.

3. REPRESENTATIONS AND WARRANTIES OF PURCHASER AND ACACIA

The Purchaser and Acacia represents and warrants, to and for the

benefit of Seller, as of the Closing Date, as follows:

13

<PAGE>

3.1. DUE ORGANIZATION; GOOD STANDING. Each of the Purchaser and Acacia

is a corporation duly organized, validly existing and in good standing under the

laws of the State of Delaware.

3.2. AUTHORITY; BINDING NATURE OF AGREEMENTS. Each of the Purchaser and

Acacia has the requisite corporate power and authority to enter into and perform

its obligations under the Transactional Agreements to which it is a party. Each

of the Purchaser and Acacia and their respective board of directors have taken

all necessary corporate action to duly authorize the execution, delivery and

performance of the Transactional Agreements to which the Acacia or Purchaser is

a party. This Agreement, and upon the execution and delivery of the additional

Transactional Agreements at the Closing, the Transactional Agreements,

constitute legal, valid and binding obligations of the Purchaser and Acacia, as

applicable, (with respect to the Transactional Agreements to which the Purchaser

or Acacia is a party), enforceable against the Purchaser and Acacia, as

applicable, in accordance with their terms, subject to (i) laws of general

application relating to bankruptcy, insolvency, reorganization, moratorium and

the relief of debtors, and (ii) rules of law governing specific performance,

injunctive relief or other equitable remedies.

3.3.