TABLE OF CONTENTS

i

AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT

THIS AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT is dated January 26, 2005 and is by and among Blackstone Capital Partners (Cayman) Ltd. 1, an exempted company incorporated under the laws of the Cayman Islands (“ BCP 1 ”), Blackstone Capital Partners (Cayman) Ltd. 2, an exempted company incorporated under the laws of the Cayman Islands (“ BCP 2 ”), Blackstone Capital Partners (Cayman) Ltd. 3, an exempted company incorporated under the laws of the Cayman Islands (“ BCP 3 ”), BA Capital Investors Sidecar Fund, L.P., a Cayman Islands limited partnership (“ BACI ”), and Celanese Corporation, a Delaware corporation (formerly known as Blackstone Crystal Holdings Capital Partners (Cayman) IV Ltd.) (together with any successor thereto, the “ Company ”).

BACKGROUND

1.             In connection with the consummation of the voluntary public takeover offer by a subsidiary of the Company for all of the outstanding registered ordinary shares of Celanese AG, a German stock corporation, the Blackstone Entities (as defined in Section 1.1) and BACI acquired ordinary shares, par value $0.01 per share (the “ Ordinary Shares ”), of the Company.

2.             The Blackstone Entities and BACI entered into the Registration Rights Agreement, dated as of April 6, 2004 (the “ Original Agreement ”) to provide for certain matters relating to their holdings of Ordinary Shares.

3.             On November 3, 2004, the Company migrated from the Cayman Islands to the State of Delaware, redomiciled itself as a Delaware corporation and changed its name from “Blackstone Crystal Holdings Capital Partners (Cayman) IV Ltd.” to “Celanese Corporation.”

4.             In connection with, and effective upon, the Initial Public Offering (as defined in Section 1.1) of the Company, and in accordance with Section 4.2 of the Original Agreement, the parties to the Original Agreement wish to amend and restate the Original Agreement in its entirety in order to set forth certain understandings regarding their holdings of Common Stock following consummation of the Initial Public Offering.

The parties agree as follows:

ARTICLE I

DEFINITIONS

SECTION 1.1          Certain Definitions .  As used in this Agreement:

“ Affiliate ” means, with respect to any Person, (i) any Person that directly or indirectly controls, is controlled by or is under common control with, such Person or (ii) any director, officer, member, partner (including limited partners) or employee of such Person or any Person specified in clause (i) above; provided , that officers, directors or employees of the Company will be deemed not to be Affiliates of the Shareholders for

purposes hereof solely by reason of being officers, directors or employees of the Company.

“ Agreement ” means this Amended and Restated Registration Rights Agreement, as the same may be amended, supplemented or otherwise modified from time to time.

“ BACI ” has the meaning set forth in the preamble.

“ BCP 1 ” has the meaning set forth in the preamble.

“ BCP 2 ” has the meaning set forth in the preamble.

“ BCP 3 ” has the meaning set forth in the preamble.

“ Blackstone Entities ” means collectively BCP 1, BCP 2, BCP 3 and/or any Affiliate of BCP 1, BCP 2, or BCP 3 that holds Registrable Securities.

“ Business Day ” means a day other than a Saturday, Sunday, federal or New York State holiday or other day on which commercial banks in New York City are authorized or required by law to close.

“ Common Stock ” means the shares of Series A common stock and Series B common stock, par value $0.0001 per share, of the Company, and any other capital stock of the Company into which such stock is reclassified or reconstituted and any other common stock of the Company.

“ Common Stock Equivalents ” means any security or obligation which is by its terms convertible, exchangeable or exercisable into or for shares of Common Stock, whether at the time of issuance or upon the passage of time or the occurrence of some future event.

“ Company ” has the meaning set forth in the preamble.

“ Designated Counsel ” means counsel to the selling Shareholders participating in a registration pursuant hereto which counsel is selected by the holders of a majority of the Registrable Securities being registered in the relevant registration.

“ Employee Stockholders ” has the meaning ascribed thereto in the Employee Stockholders’ Agreement.

“ Employee Stockholders’ Agreement ” means the Employee Stockholders’ Agreement, dated as of January 26, 2005, by and among Celanese Corporation and the other parties named therein (as the same may be amended, supplemented, restated or otherwise modified from time to time).

“ Holdback Period ” has the meaning set forth in Section 2.3.

2

“ Initial Public Offering ” means the closing of the first sale of common equity or equivalent securities of the Company to the public pursuant to an effective registration statement (other than a registration statement on Form S-4 or S-8 or any similar or successor form) filed under the Securities Act.

“ Inspector ” has the meaning set forth in Section 2.4(k).

“ Ordinary Shares ” has the meaning set forth in the preamble.

“ Person ” means any individual, corporation, limited liability company, partnership, trust, joint stock company, business trust, unincorporated association, joint venture, governmental authority or other entity of any nature whatsoever.

“ Registrable Securities ” means (x) any shares of Common Stock, (y) any shares of Common Stock owned or to be acquired upon conversion, exercise or exchange of Common Stock Equivalents and (z) any shares of Common Stock owned or to be acquired in connection with a recapitalization, merger, consolidation, exchange or other reorganization of the Company (or any successor entity), in each case now or hereafter owned by the Shareholders.  As to any particular Registrable Securities, once issued, such Registrable Securities shall cease to be Registrable Securities when (i) a registration statement with respect to the sale by the applicable Shareholder of such securities has become effective under the Securities Act and such securities have been disposed of in accordance with such registration statement, (ii) such securities have been distributed to the public pursuant to Rule 144 (or any successor provision) under the Securities Act, (iii) such securities have been otherwise transferred, new certificates for such securities not bearing a legend restricting further transfer have been delivered by the Company and subsequent disposition of such securities does not require registration or qualification of such securities under the Securities Act or any state securities or blue sky law then in force, (iv) such securities are sold to a Person in a transaction in which rights under provisions of this Agreement are not assigned in accordance with this Agreement, or (v) such securities have ceased to be outstanding.

“ Registration Expenses ” means all expenses incident to the Company’s performance of or compliance with this Agreement, including, without limitation, all SEC and stock exchange or National Association of Securities Dealers, Inc. (the “ NASD ”) registration and filing fees and expenses, fees and expenses of compliance with securities or blue sky laws (including fees and disbursements of counsel for any underwriters in connection with blue sky qualifications of the Registrable Securities), rating agency fees, printing expenses, messenger, telephone and delivery expenses, the fees and expenses incurred in connection with the listing of the securities to be registered on any securities exchange or national market system, fees and disbursements of counsel for the Company and all independent certified public accountants (including the expenses of any annual audit, special audit and “cold comfort” letters required by or incident to such performance and compliance), securities laws liability insurance (if the Company so desires (or if the underwriters of the applicable offering so require)), the fees and disbursements of underwriters (including, without limitation, all fees and expenses of any “qualified independent underwriter” required by the rules of the NASD) customarily paid

3

by issuers or sellers of securities in public equity offerings, the expenses customarily borne by the issuers of securities in a “road show” presentation to potential investors, the fees and expenses of any special experts retained by the Company in connection with such registration, the fees and expenses of other persons retained by the Company and all fees and expenses of any selling Shareholder participating in a registration pursuant hereto (including fees and expenses of Designated Counsel), other than underwriting discounts or commissions or transfer taxes, if any, attributable to the sale of shares of Registrable Securities by such selling Shareholder.

“ SEC ” means the U.S. Securities and Exchange Commission.

“ Securities Act ” means the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder, as the same may be amended from time to time.

“ Shareholders ” means each of the Blackstone Entities and BACI collectively, and “ Shareholder ” means any one of the Shareholders.

“ Transferee ” means any Person to whom any Shareholder or any Transferee thereof transfers Registrable Securities.

SECTION 1.2          Other Definitional Provisions; Interpretation .

(a)           The words “ hereof ,” “ herein ,” and “ hereunder ” and words of similar import when used in this Agreement refer to this Agreement as a whole and not to any particular provision of this Agreement, and section and subsection references are to this Agreement unless otherwise specified.

(b)           The headings in this Agreement are included for convenience of reference only and do not limit or otherwise affect the meaning or interpretation of this Agreement.

(c)           The meanings given to terms defined herein are equally applicable to both the singular and plural forms of such terms.

ARTICLE II

REGISTRATION RIGHTS

SECTION 2.1          Incidental Registration .

(a)           If the Company proposes to register any of its securities under the Securities Act (other than a registration statement on Form S-4 or S-8), whether or not for its own account (and including any registration pursuant to a request or demand right of any other Person), then the Company will each such time give prompt written notice thereof to the Shareholders of their rights under this Section 2.1, at least 15 Business Days prior to the anticipated filing date of such registration statement.  Such notice shall offer the Shareholders the opportunity to include in such registration statement such number of Registrable Securities as each Shareholder may request.  Upon the written request of any Shareholder made within 15 Business Days after the receipt of any such notice from the Company, which request shall specify the number of

4

Registrable Securities intended to be disposed of by such Shareholder in such offering, the Company will use its reasonable best efforts to effect the registration under the Securities Act, as expeditiously as is possible, of all the Registrable Securities which the Company has been so requested to register by the Shareholders, subject to Section 2.1(b); provided , that until the six-month anniversary of the Initial Public Offering (or such shorter period as the underwriters for such Initial Public Offering shall require of either the Blackstone Entities or BACI), BACI shall not be permitted to include any Registrable Securities in such registration unless any of the Blackstone Entities include any Registrable Securities in such registration; provided , further , that if, at any time after giving written notice of its intention to register any securities and prior to the effective date of the registration statement filed in connection with such registration, the Company or any other holder of securities that initiated such registration (an “ Initiating Holder ”) shall determine for any reason not to proceed with the proposed registration, the Company may at its election (or the election of such Initiating Holder(s) as applicable) give written notice of such determination to the Shareholders and thereupon shall be relieved of its obligation to register any Registrable Securities in connection with such registration (but not from its obligation to pay the Registration Expenses incurred in connection therewith).

(b)           If a registration pursuant to this Section 2.1 involves an underwritten offering and the managing underwriter advises the Company in writing that, in its opinion, the number of securities which the Company and the holders of the Registrable Securities and any other Persons intend to include in such registration exceeds the maximum number of securities which can be sold in such offering without having an adverse effect on such offering (including the price at which such securities can be sold), then the number of such securities to be included in such registration shall be reduced to such extent, and the Company will include in such registration such maximum number of securities as follows: (i) if such registration has been initiated by a Demand Party, then in the manner provided in Section 2.2(b); or (ii) if such registration has been initiated by the Company, then (A) first , all of the securities the Company proposes to sell for its own account, if any; and (B)  second , such number of Registrable Securities requested to be included in such registration by the Shareholders and such number of securities of the Company requested to be included in such registration by any other holders of securities of the Company (including any Employee Stockholders) having equivalent rights under similar agreements (including the Employee Stockholders’ Agreement), which, in the opinion of such managing underwriter can be sold without having the adverse effect described above, which number of securities shall be allocated pro rata among such Shareholders and such other holders on the basis of the relative number of Registrable Securities then held by each such Shareholder and the number of securities subject to such equivalent rights held by such other holders; provided , that any such amount thereby allocated to each such Shareholder or such other holder of such securities that exceeds such Shareholder’s or such other holder’s request shall be reallocated among the Shareholders and such other holders in like manner, as applicable.

(c)           The Company will pay all Registration Expenses in connection with each registration of Registrable Securities pursuant to this Section 2.1.

SECTION 2.2           Demand Registration .  (a)  Upon the written request from time to time (a “ Request ”) of any of the Blackstone Entities (a “ Demand Party ”) that the Company effect the registration under the Securities Act of all or part of such Demand Party’s Registrable Securities and specifying the amount and intended method of disposition thereof, the Company

5

will promptly give written notice of such requested registration to the other Shareholders and, as expeditiously as possible, use its reasonable best efforts to effect the registration under the Securities Act of:

(1)           such Registrable Securities which the Company has been so requested to register by the Demand Party; and

(2)           the Registrable Securities of other Shareholders which the Company has been requested to register by written request given to the Company within 10 days after the giving of such written notice by the Company (which request shall specify the amount and intended method of disposition of such securities).

The Demand Party shall have the right to select the managing underwriter or underwriters to administer the offerings covered by its Requests.

(b)           If a requested registration pursuant to this Section 2.2 involves an underwritten offering and the managing underwriter advises the Company in writing that, in its opinion, the number of securities requested to be included in such registration exceeds the maximum number of securities which can be sold in such offering without having an adverse effect on such offering (including the price at which such securities can be sold), then the number of such securities to be included in such registration shall be reduced to such extent, and the Company will include in such registration such maximum number of securities as follows: (i) first , the number of Registrable Securities requested to be included in such registration by the Shareholders, which number shall be allocated pro rata among all such requesting Shareholders based on the relative number of Registrable Securities then held by each such requesting Shareholder; (ii) second , the number of securities of the Company requested to be registered by holders of securities (including any Employee Stockholders) having equivalent rights under similar agreements (including the Employee Stockholders’ Agreement); and (iii) third , the number of securities of the Company proposed to be sold by the Company, if any.

(c)           If a requested registration pursuant to this Section 2.2 involves an underwritten offering and the managing underwriter advises the Company that, in its opinion, certain disclosure is of material importance to the success of such proposed offering, then the Company shall cooperate with the managing underwriter to provide such disclosure.  The Company agrees to include in any registration statement all information which, in the reasonable view of counsel to the underwriters (if any) or Designated Counsel, is required to be included.

(d)           The Demand Party shall be permitted to request that any registration under this Section 2.2 be made under Rule 415 under the Securities Act (the “ Shelf Registration ”).  The Company shall use its commercially reasonable efforts to effect such Shelf Registration and to keep it continuously effective until such date on which there are no Registrable Securities covered by such registration.  During the period during which the Shelf Registration is effective, the Company shall supplement or make amendments to the Shelf Registration, if required by the Securities Act or if reasonably requested by the Demand Party or an underwriter of Registrable Securities to be sold pursuant thereto, including to reflect any specific plan of distribution or method of sale, and shall use its reasonable best efforts to have such supplements and amendments declared effective, if required, as soon as practicable after filing.

6

(e)           The Company will pay all Registration Expenses in connection with each registration of Registrable Securities pursuant to this Section 2.2.

SECTION 2.3          Holdback .

(a)           Restrictions on Sale by the Shareholders .  In connection with any underwritten public offering of securities of the Company, each Shareholder agrees not to effect any sale or distribution, including any sale pursuant to Rule 144 under the Securities Act, of any Registrable Securities, and not to effect any sale or distribution of other securities of the Company or of any securities convertible into or exchangeable or exercisable for any other securities of the Company (in each case, other than as part of such underwritten public offering) in each case, during the seven days prior to, and during such period as the managing underwriter may require (not to exceed 90 days, or, in the case of the Initial Public Offering, 180 days) (the period during which such restriction applies, the “ Holdback Period ”) beginning on, the closing date of the sale of such securities pursuant to an effective registration statement, except as part of such registration; provided , however , that this provision shall not apply if (i) such Shareholder owns, at the time of such registration and throughout the Holdback Period, less than 2% of all outstanding shares of Common Stock and (ii) such Shareholder is not participating in such public offering.

(b)           Restrictions on Sale by the Company and Others .  In connection with any underwritten public offering of securities of the Company, the Company agrees (i) not to effect any sale or distribution, and to use its reasonable best efforts to cause its directors and officers not to effect any sale or distribution, of any shares of Common Stock, Common Stock Equivalents or other securities of the Company or of any security convertible into or exchangeable or exercisable for any shares of Common Stock, Common Stock Equivalents or other securities of the Company (other than in connection with an employee stock option or other benefit plans) during the seven days prior to, and during the same period applicable to the Shareholders in connection with such offering pursuant to Section 2.3(a) beginning on, the closing date of the sale of such securities pursuant to an effective registration statement, except as part of such registration, and (ii) that any agreement entered into after the date of this Agreement pursuant to which the Company issues or agrees to issue any privately placed shares of Common Stock, Common Stock Equivalents or other equity securities shall contain a provision under which holders of such securities agree not to effect any sale or distribution of any such securities during the period referred to in the foregoing clause (i), except as part of such registration, if permitted.

SECTION 2.4           Other Registration-Related Matters .  If and whenever the Company is required to use its reasonable best efforts to effect or cause the registration of any Registrable Securities under the Securities Act as provided in this Agreement, the Company will, as expeditiously as possible:

(a)           in the case of a registration as provided in this Agreement, use its reasonable best efforts to prepare and file with the SEC within 45 days (or, in the case of a registration statement on Form S-3, within seven days) after receipt of a request for registration with respect to such Registrable Securities, a registration statement on any form for which the Company then qualifies or which counsel for the Company shall deem

7

appropriate, and which form shall be available for the sale of the Registrable Securities in accordance with the intended methods of distribution thereof, and use its reasonable best efforts to cause such registration statement to become and remain effective as promptly as practicable, subject to the right of the Demand Party to defer the Company’s request for the acceleration of effectiveness of any such registration statement as may be necessary to accommodate the anticipated timetable for such offering; provided , that before filing with the SEC a registration statement or prospectus or any