GUARANTY AGREEMENT

Exhibit 10.21

GUARANTY AGREEMENT

           THIS GUARANTY AGREEMENT (this “ Guaranty ”) is executed as of July 31, 2007, by CAPITALSOURCE INC. , a Delaware corporation, having an address at c/o CapitalSource Finance LLC, 4445 Willard Avenue, 12th Floor, Chevy Chase, MD 20815 (“ Guarantor ”), for the benefit of COLUMN FINANCIAL, INC. , a Delaware corporation, having an address at 11 Madison Avenue, New York, New York 10010 (“ Lender ”).

W I T N E S S E T H  :

           WHEREAS , pursuant to that certain Promissory Note, dated of even date herewith, executed by CSE Casablanca Holdings II LLC (“ Borrower ”), and payable to the order of Lender in the original principal amount of Thirty Six Million One Hundred Forty Thousand Nine Hundred Eighty One and 00/100 Dollars ($36,140,981.00) (as the same may be amended, restated, replaced, supplemented, or otherwise modified from time to time, the “ Note ”), Borrower has become indebted, and may from time to time be further indebted, to Lender with respect to a loan (“ Loan ”), made pursuant to that certain Mezzanine Loan Agreement, of even date herewith, between Borrower and Lender (as the same may be amended, restated, replaced, supplemented, or otherwise modified from time to time, the “ Loan Agreement ”), which Loan is secured by, among other things, the liens and security interests of a certain Pledge and Security Agreement, dated as of the date hereof (as the same may be amended, restated, replaced, supplemented, or otherwise modified from time to time, collectively, the “ Pledge Agreement ”), pursuant to which Borrower has pledged its ownership interests in certain companies identified therein (the “Pledged Companies”) and further evidenced, secured or governed by other instruments and documents executed in connection with the Loan (together with the Note, the Loan Agreement and Pledge Agreement, the “ Loan Documents ”); and

           WHEREAS , Borrower is the sole member of the Pledged Companies and the owner of direct or indirect interests in the Mortgage Borrowers (as defined in the Loan Agreement); and

           WHEREAS , Lender is not willing to make the Loan, or otherwise extend credit, to Borrower unless Guarantor enters into this Guaranty; and

           WHEREAS , Guarantor is the owner of a direct or indirect interest in Borrower, and Guarantor will directly benefit from Lender’s making the Loan to Borrower.

           NOW, THEREFORE , as an inducement to Lender to make the Loan to Borrower, and for other good and valuable consideration, the receipt and legal sufficiency of which are hereby acknowledged, the parties do hereby agree as follows:

ARTICLE I

NATURE AND SCOPE OF GUARANTY

           1.1 Guaranty of Obligation . Guarantor hereby irrevocably and unconditionally guarantees to Lender and its successors and assigns the payment and performance of the Guaranteed Obligations as and when the same shall be due and payable, whether by lapse of time, by acceleration of maturity or otherwise. Guarantor hereby irrevocably and unconditionally covenants and agrees that it is liable for the Guaranteed Obligations as a primary obligor.

           1.2 Definition of Guaranteed Obligations . (a) As used herein, the term “ Guaranteed Obligations ” means (i) the obligations and liabilities of Borrower to Lender for any loss, damage, cost, expense, liability, claim or other obligation incurred by Lender (including reasonable attorneys’ fees and costs reasonably incurred) arising out of or in connection with any of the following, which Guaranteed Obligations shall also include events arising from and after December 1, 2006:

               (A) fraud or intentional misrepresentation by Borrower, any Mortgage Borrower, Guarantor or any Affiliate thereof in connection with the Loan or the Original Loan;

               (B) waste by Borrower, any Mortgage Borrower, Guarantor or any Affiliate thereof to one or more of the Individual Properties;

               (C) the gross negligence or willful misconduct of Borrower, any Mortgage Borrower, Guarantor or any Affiliate thereof;

               (D) the breach of any representation, warranty, covenant or indemnification provision in the Environmental Indemnity concerning environmental laws, hazardous substances and asbestos and any indemnification of Lender with respect thereto;

               (E) the removal or disposal by Borrower, any Mortgage Borrower, Guarantor or any Affiliate of any portion of one or more of the Properties after the occurrence and during the continuance of an Event of Default;

               (F) the misappropriation or conversion by Borrower or any Mortgage Borrower, of (A) any Insurance Proceeds paid by reason of any Casualty, (B) any Awards received in connection with a Condemnation, (C) any Rents after the occurrence and during the continuance of an Event of Default, or (D) any Rents paid more than one (1) month in advance;

               (G) failure to pay charges for labor or materials or other charges incurred by the Borrower that create Liens on any portion of the Properties;

               (H) any security deposits, advance deposits or any other deposits collected or held by Borrower, any Mortgage Borrower, Guarantor or any Affiliate thereof with respect to the Properties which are not delivered to the Senior Lender upon a foreclosure of the Properties or acceptance of a deed in lieu thereof, except to the extent any such deposits were

applied in accordance with the terms and conditions of any of the Leases prior to the occurrence of the Event of Default that gave rise to such foreclosure or action in lieu thereof;

               (I) any amounts received by Borrower or any Affiliate thereof that are not deposited into the Lockbox Account to the extent required to be so deposited under the Cash Management Agreement or the Loan Agreement;

               (J) if (1) Borrower or any Mortgage Borrower, fails to permit on-site inspections of any of the Properties, subject to terms of each respective Operating Lease, upon the request of Lender or (2) Borrower fails to provide financial information concerning Borrower, any Mortgage Borrower, Principal or Guarantor in its possession (or financial information which could be obtained by Borrower through commercially reasonable efforts) or (3) Borrower fails to provide financial information in its possession or control (or financial information which could be obtained by Borrower through commercially reasonable efforts) concerning any Operator Tenant or collections under the Operating Leases, in each case, to the extent required by and in accordance with the terms and provisions of the Loan Agreement;

               (K) any breach of the representations and warranties set forth in Section 4.1.30(a) and (b) of the Loan Agreement (except for any representation or warranty that Borrower will remain solvent, maintain adequate capital or pay its debts or liabilities as the same may become due).

          Notwithstanding anything to the contrary in this Guaranty, the Loan Agreement, the Note or any of the Loan Documents, Guarantor shall be liable for the full amount of the Debt: (A) in the event of: (I) Borrower or any Mortgage Borrower, filing a voluntary petition under the Bankruptcy Code or any other Federal or state bankruptcy or insolvency law; (II) the filing of an involuntary petition against Borrower or any Mortgage Borrower, under the Bankruptcy Code or any other Federal or state bankruptcy or insolvency law, which is assisted, supported, aided or abetted by Borrower, any Mortgage Borrower and/or Guarantor or with respect to which Borrower, any Mortgage Borrower and/or Guarantor fails to contest (where good grounds exist for such contest); (III) Borrower or any Mortgage Borrower filing an answer consenting to or otherwise acquiescing in or joining in any involuntary petition filed against it, by any other Person under the Bankruptcy Code or any other Federal or state bankruptcy or insolvency law, or soliciting or causing to be solicited petitioning creditors for any involuntary petition from any Person; (IV) Borrower or any Mortgage Borrower consenting to or acquiescing in or joining in an application for the appointment of a custodian, receiver, trustee, or examiner for Borrower or any Mortgage Borrower or any material portion of any Property or the Collateral; or (V) Borrower or any Mortgage Borrower making a general assignment for the benefit of creditors, or admitting, in writing or in any legal proceeding, its insolvency or inability to pay its debts as they become due; (B) if Borrower or any Mortgage Borrower fails to maintain its status as a Single Purpose Entity as required by, and in accordance with, the terms and provisions of the Loan Agreement or the other Loan Documents (except for any covenant to remain solvent, maintain adequate capital or pay its debts or liabilities as the same may become due or the additional covenant to comply with any assumptions in the Insolvency Opinion or any Additional Insolvency Opinion); (C) if Borrower or any Mortgage Borrower fails to obtain Lender’s prior consent to any Indebtedness or voluntary Lien encumbering one or more of the

Individual Properties or the Collateral or any material portion of one or more of the Individual Properties or all or any part of the Collateral to the extent required by the Loan Agreement; or (D) if Borrower fails to obtain Lender’s prior consent to any Transfer (other than a foreclosure, or acceptance of a deed in lieu of foreclosure, with respect to one or more of the Properties by the Senior Lender or a foreclosure by Lender, or Lender’s acceptance of an assignment in lieu of foreclosure, with respect to all or part of the Pledged Collateral) to the extent required by the Loan Agreement.

          (b) Notwithstanding anything to the contrary in any of the Loan Documents, Lender shall not be deemed to have waived any right which Lender may have under Section 506(a), 506(b), 1111(b) or any other provisions of the U.S. Bankruptcy Code to file a claim against Borrower or Guarantor for the full amount of the Debt secured by the Pledge Agreement or to require that all collateral shall continue to secure all of the Debt owing to Lender in accordance with the Loan Documents. Notwithstanding anything to the contrary contained herein, this Guaranty is not secured by any collateral furnished by Guarantor.

          (c) Notwithstanding anything to the contrary in any of the Loan Documents, including without limitation anything to the contrary in the immediately preceding paragraphs or elsewhere in this Guaranty, Guarantor shall not have any obligations or liabilities hereunder for any loss, damage, cost, expense, liability, claim or other obligation incurred by Lender (including reasonable attorneys’ fees and costs reasonably incurred) arising out of or in connection with (i) any action or inaction of any Pledged Company or any entity owned or controlled by any Pledged Company but only to the extent such action or inaction results from the exercise of control over any such Pledged Company or such entity owned or controlled by any Pledged Company by Lender, (ii) any action or omission which occurs after the completion of a private or public sale of the Pledged Company Interests (as defined in the Pledge Agreement) or after the acceptance of an assignment in lieu of foreclosure with respect to the Pledged Company Interests, or (iii) any action or omission relating to any Individual Property which occurs after the Lender completes a foreclosure with respect to such Individual Property or accepts a deed in lieu of foreclosure with respect to such Individual Property.

           1.3 Nature of Guaranty . This Guaranty is an irrevocable, absolute, continuing guaranty of payment and performance and not a guaranty of collection. This Guaranty may not be revoked by Guarantor and shall continue to be effective with respect to any Guaranteed Obligations arising or created after any attempted revocation by Guarantor. The fact that at any time or from time to time the Guaranteed Obligations may be increased or reduced shall not release or discharge the obligation of Guarantor to Lender with respect to the Guaranteed Obligations. This Guaranty may be enforced by Lender and any subsequent holder of the Note and shall not be discharged by the assignment or negotiation of all or part of the Note.

           1.4 Guaranteed Obligations Not Reduced by Offset . The Guaranteed Obligations and the liabilities and obligations of Guarantor to Lender hereunder, shall not be reduced, discharged or released because or by reason of any existing or future offset, claim or defense of Borrower, or any other party (except by Borrower’s or Guarantor’s performance of such obligations and then only to the extent of such performance), against Lender or against

payment of the Guaranteed Obligations, whether such offset, claim or defense arises in connection with the Guaranteed Obligations (or the transactions creating the Guaranteed Obligations) or otherwise.

           1.5 Payment By Guarantor . If all or any part of the Guaranteed Obligations shall not be punctually paid when due, whether upon demand, maturity, acceleration or otherwise, Guarantor shall, immediately upon demand by Lender, and without presentment, protest, notice of protest, notice of non-payment, notice of intention to accelerate the maturity, notice of acceleration of the maturity, or any other notice whatsoever, pay in lawful money of the United States of America, the amount due on the Guaranteed Obligations to Lender at Lender’s address as set forth herein. Such demand(s) may be made at any time coincident with or after the time for payment of all or part of the Guaranteed Obligations, and may be made from time to time with respect to the same or different items of Guaranteed Obligations. Such demand shall be deemed made, given and received in accordance with the notice provisions hereof.

           1.6 No Duty To Pursue Others . It shall not be necessary for Lender (and Guarantor hereby waives any rights which Guarantor may have to require Lender), in order to enforce the obligations of Guarantor hereunder, first to (a) institute suit or exhaust its remedies against Borrower or others liable on the Loan or the Guaranteed Obligations or any other person, (b) enforce Lender’s rights against any collateral which shall ever have been given to secure the Loan, (c) enforce Lender’s rights against any other guarantors of the Guaranteed Obligations, (d) join Borrower or any others liable on the Guaranteed Obligations in any action seeking to enforce this Guaranty, (e) exhaust any remedies available to Lender against any collateral which shall ever have been given to secure the Loan, or (f) resort to any other means of obtaining payment of the Guaranteed Obligations. Lender shall not be required to mitigate damages or take any other action to reduce, collect or enforce the Guaranteed Obligations.

           1.7 Waivers . Guarantor acknowledges and consents to the provisions of the Loan Documents, and hereby waives notice of (a) any loans or advances made by Lender to Borrower, (b) acceptance of this Guaranty, (c) any amendment or extension of the Note, the Loan Agreement or of any other Loan Documents, (d) the execution and delivery by Borrower and Lender of any other loan or credit agreement or of Borrower’s execution and delivery of any promissory notes or other documents arising under the Loan Documents or in connection with the Properties or the Collateral, (e) the occurrence of any breach by Borrower or an Event of Default, (f) Lender’s transfer or disposition of the Guaranteed Obligations, or any part thereof, (g) sale or foreclosure (or posting or advertising for sale or foreclosure) of any collateral for the Guaranteed Obligations, (h) protest, proof of non-payment or default by Borrower and (i) any other action at any time taken or omitted by Lender, and, generally, all demands and notices of every kind in connection with this Guaranty, the Loan Documents, any documents or agreements evidencing, securing or relating to any of the Guaranteed Obligations.

           1.8 Payment of Expenses . In the event that Guarantor should breach or fail to timely perform any provisions of this Guaranty, Guarantor shall, immediately upon demand by Lender, pay Lender all costs and expenses (including court costs and reasonable attorneys’ fees) incurred by Lender in the enforcement hereof or the preservation of Lender’s rights hereunder. The covenant contained in this Section shall survive the payment and performance of the Guaranteed Obligations.

           1.9 Effect of Bankruptcy . In the event that, pursuant to any insolvency, bankruptcy, reorganization, receivership or other debtor relief law, or any judgment, order or decision thereunder, Lender must rescind or restore any payment, or any part thereof, received by Lender in satisfaction of the Guaranteed Obligations, as set forth herein, any prior release or discharge from the terms of this Guaranty given to Guarantor by Lender shall be without effect, and this Guaranty shall remain in full force and effect. It is the intention of Borrower and Guarantor that Guarantor’s obligations hereunder shall not be discharged except by Guarantor’s performance of such obligations and then only to the extent of such performance.

           1.10 Waiver of Subrogation, Reimbursement and Contribution . Notwithstanding anything to the contrary contained in this Guaranty, Guarantor hereby unconditionally and irrevocably waives, releases and abrogates, prior to the payment in full of the Loan and for a period of 91 days thereafter any and all rights it may now or hereafter have under any agreement, at law or in equity (including, without limitation, any law subrogating the Guarantor to the rights of Lender), to assert any claim against or seek c