<PAGE>

                                                                   EXHIBIT 10.33

                               GUARANTY OF PAYMENT

         GUARANTY OF PAYMENT, MADE AS OF DECEMBER 17, 2003 (THIS "GUARANTY"),
BETWEEN EQUITY OFFICE PROPERTIES TRUST, A MARYLAND REAL ESTATE INVESTMENT TRUST,
HAVING AN ADDRESS AT TWO NORTH RIVERSIDE PLAZA, SUITE 2100, CHICAGO, ILLINOIS
60606 ("GUARANTOR"), AND JPMORGAN CHASE BANK, AS ADMINISTRATIVE AGENT (THE
"ADMINISTRATIVE AGENT") FOR THE BANKS (THE "BANKS") LISTED ON THE SIGNATURE
PAGES OF THE Revolving Credit Agreement, dated as of December 17, 2003, among
EOP Operating Limited Partnership ("Borrower"), the banks listed on the
signature pages thereof, J.P. Morgan Securities Inc. and Citigroup Global
Markets Inc., as Joint Lead Arrangers and Joint Bookrunners, JPMorgan Chase
Bank, as Administrative Agent, Citigroup Global Markets Inc., as Syndication
Agent, and Bank One, NA, Credit Suisse First Boston, Acting Through its Cayman
Islands Branch, and UBS Loan Finance LLC, as Co-Documentation Agents (as the
same may be amended from time to time, the "Credit Agreement").

                              W I T N E S S E T H:

         WHEREAS, THE BANKS HAVE AGREED TO MAKE LOANS TO BORROWER IN THE
AGGREGATE PRINCIPAL AMOUNT NOT TO EXCEED ONE BILLION DOLLARS ($1,000,000,000)
(HEREINAFTER COLLECTIVELY REFERRED TO AS THE "LOANS");

         WHEREAS, THE LOANS ARE EVIDENCED BY CERTAIN PROMISSORY NOTES (THE
"NOTES") OF BORROWER MADE TO EACH OF THE BANKS IN ACCORDANCE WITH THE TERMS OF
THE CREDIT AGREEMENT;

         WHEREAS, THE CREDIT AGREEMENT AND THE NOTES AND ANY OTHER DOCUMENTS
EXECUTED IN CONNECTION THEREWITH ARE HEREINAFTER COLLECTIVELY REFERRED TO AS THE
"LOAN DOCUMENTS";

         WHEREAS, CAPITALIZED TERMS USED HEREIN AND NOT OTHERWISE DEFINED SHALL
HAVE THE MEANINGS ASCRIBED THERETO IN THE CREDIT AGREEMENT;

         WHEREAS, GUARANTOR IS THE SOLE GENERAL PARTNER OF BORROWER; AND

         WHEREAS, AS A CONDITION TO THE EXECUTION AND DELIVERY OF THE LOAN
DOCUMENTS, THE BANKS HAVE REQUIRED THAT GUARANTOR EXECUTE AND DELIVER THIS
GUARANTY; AND

         NOW THEREFORE, IN CONSIDERATION OF THE PREMISES AND THE BENEFITS TO BE
DERIVED FROM THE MAKING OF THE LOANS BY THE BANKS TO BORROWER, AND IN ORDER TO
INDUCE THE ADMINISTRATIVE AGENT, THE SYNDICATION AGENT, THE CO-DOCUMENTATION
AGENTS, AND THE BANKS TO ENTER INTO THE CREDIT AGREEMENT AND THE OTHER LOAN
DOCUMENTS, THE GUARANTOR HEREBY AGREES AS FOLLOWS:

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         1.       Guarantor, on behalf of itself and its successors and assigns,
hereby irrevocably, absolutely and unconditionally guarantees the full and
punctual payment when due, whether at stated maturity or otherwise, of all
Obligations of Borrower now or hereafter existing under the Notes and the Credit
Agreement, for principal and/or interest as well as any and all other amounts
due thereunder, including, without limitation, all indemnity obligations of
Borrower thereunder, and any and all reasonable costs and expenses (including,
without limitation, reasonable attorneys' fees and disbursements) incurred by
the Administrative Agent, the Syndication Agent, the Co-Documentation Agents, or
the Banks in enforcing their rights under this Guaranty (all of the foregoing
obligations being the "Guaranteed Obligations").

         2.       It is agreed that the Guaranteed Obligations of Guarantor
hereunder are primary and this Guaranty shall be enforceable against Guarantor
and its successors and assigns without the necessity for any suit or proceeding
of any kind or nature whatsoever brought by the Administrative Agent or any of
the Banks against Borrower or its respective successors or assigns or any other
party or against any security for the payment and performance of the Guaranteed
Obligations and without the necessity of any notice of non-payment or
non-observance or of any notice of acceptance of this Guaranty or of any notice
or demand to which Guarantor might otherwise be entitled (including, without
limitation, diligence, presentment, notice of maturity, extension of time,
change in nature or form of the Guaranteed Obligations, acceptance of further
security, release of further security, imposition or agreement arrived at as to
the amount of or the terms of the Guaranteed Obligations, notice of adverse
change in Borrower's financial condition and any other fact which might
materially increase the risk to Guarantor), all of which Guarantor hereby
expressly waives; and Guarantor hereby expressly agrees that the validity of
this Guaranty and the obligations of Guarantor hereunder shall in no way be
terminated, affected, diminished, modified or impaired by reason of the
assertion of or the failure to assert by the Administrative Agent or any of the
Banks against Borrower or its respective successors or assigns, any of the
rights or remedies reserved to the Administrative Agent or any of the Banks
pursuant to the provisions of the Loan Documents. Guarantor agrees that any
notice or directive given at any time to the Administrative Agent or any of the
Banks which is inconsistent with the waiver in the immediately preceding
sentence shall be void and may be ignored by the Administrative Agent and the
Banks, and, in addition, may not be pleaded or introduced as evidence in any
litigation relating to this Guaranty for the reason that such pleading or
introduction would be at variance with the written terms of this Guaranty,
unless the Administrative Agent has specifically agreed otherwise in a writing,
signed by a duly authorized officer. Guarantor specifically acknowledges and
agrees that the foregoing waivers are of the essence of this transaction and
that, but for this Guaranty and such waivers, the Administrative Agent and the
Banks would have declined to execute and deliver the Loan Documents.

         3.       Guarantor waives, and covenants and agrees that it will not at
any time insist upon, plead or in any manner whatsoever claim or take the
benefit or advantage of, any and all appraisal, valuation, stay, extension,
marshalling-of-assets or redemption laws, or right of homestead or exemption,
whether now or at any time hereafter in force, which may delay, prevent or
otherwise affect the performance by Guarantor of its obligations under or the

                                        2
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enforcement by the Administrative Agent or any of the Banks of, this Guaranty.
Guarantor further covenants and agrees not to set up or claim any defense,
counterclaim, offset, setoff or other objection of any kind to any action, suit
or proceeding in law, equity or otherwise, or to any demand or claim that may be
instituted or made by the Administrative Agent or any of the Banks other than
the defense of the actual timely payment and performance by Borrower of the
Guaranteed Obligations hereunder; provided, however, that the foregoing shall
not be deemed a waiver of Guarantor's right to assert any compulsory
counterclaim, if such counterclaim is compelled under local law or rule of
procedure, nor shall the foregoing be deemed a waiver of Guarantor's right to
assert any claim which would constitute a defense, setoff, counterclaim or
crossclaim of any nature whatsoever against Administrative Agent or any Bank in
any separate action or proceeding. Guarantor represents, warrants and agrees
that, as of the date hereof, its obligations under this Guaranty are not subject
to any counterclaims, offsets or defenses against the Administrative Agent or
any Bank of any kind.

                  4.       The provisions of this Guaranty are for the benefit
of the Administrative Agent, the Syndication Agent, the Co-Documentation Agents,
and the Banks and their successors and permitted assigns, and nothing herein
contained shall impair as between Borrower and the Administrative Agent, the
Syndication Agent, the Co-Documentation Agents, and the Banks the obligations of
Borrower under the Loan Documents.

                  5.       This Guaranty shall be a continuing, unconditional
and absolute guaranty and the liability of Guarantor hereunder shall in no way
be terminated, affected, modified, impaired or diminished by reason of the
happening, from time to time, of any of the following, although without notice
or the further consent of Guarantor:

                  (1)      any assignment, amendment, modification or waiver of
         or change in any of the terms, covenants, conditions or provisions of
         any of the Guaranteed Obligations or the Loan Documents or the
         invalidity or unenforceability of any of the foregoing; or

                  (2)      any extension of time that may be granted by the
         Administrative Agent to Borrower, any guarantor, or their respective
         successors or assigns, heirs, executors, administrators or personal
         representatives; or

                  (3)      any action which the Administrative Agent, the
         Syndication Agent, the Co-Documentation Agents, the Arrangers and/or
         the Banks may take or fail to take under or in respect of any of the
         Loan Documents or by reason of any waiver of, or failure to enforce any
         of the rights, remedies, powers or privileges available to the
         Administrative Agent under this Guaranty or available to the
         Administrative Agent, the Syndication Agent, the Co-Documentation
         Agents, the Arrangers and/or the Banks at law, equity or otherwise, or
         any action on the part of the Administrative Agent, the Syndication
         Agent, the Co-Documentation Agents, the Arrangers and/or the Banks
         granting indulgence or extension in any form whatsoever; or

                  (4)      any sale, exchange, release, or other disposition of
         any property pledged,

                                        3
<PAGE>

         mortgaged or conveyed, or any property in which the Administrative
         Agent and/or the Banks have been granted a lien or security interest to
         secure any indebtedness of Borrower to the Administrative Agent and/or
         the Banks; or

                  (5)      any release of any person or entity who may be liable
         in any manner for the payment and collection of any amounts owed by
         Borrower to the Administrative Agent, the Syndication Agent, the
         Co-Documentation Agents, the Arrangers and/or the Banks; or

                  (6)      the application of any sums by whomsoever paid or
         however realized to any amounts owing by Borrower to the Administrative
         Agent, the Syndication Agent, the Co-Documentation Agents, the
         Arrangers and/or the Banks under the Loan Documents in such manner as
         the Administrative Agent shall determine in its sole discretion; or

                  (7)      Borrower's or any guarantor's voluntary or
         involuntary liquidation, dissolution, sale of all or substantially all
         of their respective assets and liabilities, appointment of a trustee,
         receiver, liquidator, sequestrator or conservator for all or any part
         of Borrower's or Guarantor's assets, insolvency, bankruptcy, assignment
         for the benefit of creditors, reorganization, arrangement, composition
         or readjustment, or the commencement of other similar proceedings
         affecting Borrower or any guarantor or any of the assets of any of
         them, including, without limitation, (i) the release or discharge of
         Borrower or any guarantor from the payment and performance of their
         respective obligations under any of the Loan Documents by operation of
         law, or (ii) the impairment, limitation or modification of the
         liability of Borrower or any guarantor in bankruptcy, or of any remedy
         for the enforcement of the Guaranteed Obligations under any of the Loan
         Documents, or Guarantor's liability under this Guaranty, resulting from
         the operation of any present or future provisions of the Bankruptcy
         Code or other present or future federal, state or applicable statute or
         law or from the decision in any court; or

                  (8)      any improper disposition by Borrower of the proceeds
         of the Loans, it being acknowledged by Guarantor that the
         Administrative Agent, the Syndication Agent, the Arrangers, the
         Co-Documentation Agents, or any Bank shall be entitled to honor any
         request made by Borrower for a disbursement of such proceeds and that
         neither the Administrative Agent, the Syndication Agent, the
         Co-Documentation Agents, the Arrangers nor any Bank shall have any
         obligation to see the proper disposition by Borrower of such proceeds.

                  6.       Guarantor agrees that if at any time all or any part
of any payment at any time received by the Administrative Agent from Borrower or
Guarantor under or with respect to this Guaranty is or must be rescinded or
returned by the Administrative Agent, the Syndication Agent, the
Co-Documentation Agents, the Arrangers or any Bank for any reason whatsoever
(including, without limitation, the insolvency, bankruptcy or reorganization of
Borrower or Guarantor), then Guarantor's obligations hereunder shall, to the
extent of the payment rescinded or returned, be deemed to have continued in
existence notwithstanding such previous receipt by

                                        4
<PAGE>

such party, and Guarantor's obligations hereunder shall continue to be effective
or reinstated, as the case may be, as to such payment, as though such previous
payment had never been made.

                  7.       Until this Guaranty is terminated pursuant to the
terms hereof, Guarantor (i) shall have no right of subrogation against Borrower
or any entity comprising same by reason of any payments or acts of performance
by Guarantor in compliance with the obligations of Guarantor hereunder, (ii)
waives any right to enforce any remedy which Guarantor now or hereafter shall
have against Borrower or any entity comprising same by reason of any one or more
payment or acts of performance in compliance with the obligations of Guarantor
hereunder and (iii) from and after an Event of Default (as defined in the Credit
Agreement), subordinates any liability or indebtedness of Borrower or any entity
comprising same now or hereafter held by Guarantor or any affiliate of Guarantor
to the obligations of Borrower under the Loan Documents. The foregoing, however,
shall not be deemed in any way to limit any rights that Guarantor may have
pursuant to the Agreement of Limited Partnership of Borrower or which it may
have at law or in equity with respect to any other partners of Borrower.

                  8.       Guarantor represents and warrants to the
Administrative Agent, the Syndication Agent, the Co-Documentation Agents, the
Arrangers and the Banks with the knowledge that the Administrative Agent, the
Syndication Agent, the Co-Documentation Agents, the Arrangers and the Banks are
relying upon the same, as follows:

                  (1)      as of the date hereof, Guarantor is the sole general
         partner of Borrower;

                  (2)      based upon such relationships, Guarantor has
         determined that it is in its best interests to enter into this
         Guaranty;

                  (3)      this Guaranty is necessary and convenient to the
         conduct, promotion and attainment of Guarantor's business, and is in
         furtherance of Guarantor's business purposes;

                  (4)      the benefits to be derived by Guarantor from
         Borrower's access to funds made possible by the Loan Documents are at
         least equal to the obligations undertaken pursuant to this Guaranty;

                  (5)      Guarantor is solvent and has full power and legal
         right to enter into this Guaranty and to perform its obligations under
         the term hereof and (i) Guarantor is organized and validly existing
         under the laws of the State of Maryland, (ii) Guarantor has complied
         with all provisions of applicable law in connection with all aspects of
         this Guaranty, and (iii) the person executing this Guaranty has all the
         requisite power and authority to execute and deliver this Guaranty;

                  (6)      to the best of Guarantor's knowledge, there is no
         action, suit, proceeding, or investigation pending or threatened
         against or affecting Guarantor at law, in equity, in admiralty or
         before any arbitrator or any governmental department, commission,
         board,

                                        5
<PAGE>

         bureau, agency or instrumentality (domestic or foreign) which is likely
         to materially and adversely impair the ability of Guarantor to perform
         its obligations under this Guaranty;

                  (7)      the execution and delivery of and the performance by
         Guarantor of its obligations under this Guaranty have been duly
         authorized by all necessary action on the part of Guarantor and do not
         (i) violate any provision of any law, rule, regulation (including,
         without limitation, Regulation U or X of the Board of Governors of the
         Federal Reserve System of the United States), order, writ, judgment,
         decree, determination or award presently in effect having applicability
         to Guarantor or the organizational documents of Guarantor the
         consequences of which violation is likely to materially and adversely
         impair the ability of Guarantor to perform its obligations under this
         Guaranty or (ii) violate or conflict with, result in a breach of or
         constitute (with due notice or lapse of time or both) a default under
         any indenture, agreement or other instrument to which Guarantor is a
         party, or by which Guarantor or any of its property is bound, the
         consequences of which violation, conflict, breach or default is likely
         to materially and adversely impair the ability of Guarantor to perform
         its obligations under this Guaranty;

                  (8)      this Guaranty has been duly executed by Guarantor and
         constitutes the legal, valid and binding obligation of Guarantor,
         enforceable against it in accordance with its terms except as
         enforceability may be limited by applicable insolvency, bankruptcy or
         other laws affecting creditors' rights generally or general principles
         of equity, whether such enforceability is considered in a proceeding in
         equity or at law;

                  (9)      no authorization, consent, approval, license or
         formal exemption from, nor any filing, declaration or registration
         with, any Federal, state, local or foreign court, governmental agency
         or regulatory authority is required in connection with the making and
         performance by Guarantor of this Guaranty, except those which have
         already been obtained; and

                  (10)     Guarantor is not an "investment company" as that term
         is defined in, nor is it otherwise subject to regulation under, the
         Investment Company Act of 1940, as amended.

                  9.       Guarantor and Administrative Agent each acknowledge
and agree that this Guaranty is a guarantee of payment and performance and not
of collection and enforcement in respect of any obligations which may accrue to
the Administrative Agent and/or the Banks from Borrower under the provisions of
any Loan Document.

                  10.      Subject to the terms and conditions of the Credit
Agreement, and in conjunction therewith, the Administrative Agent or any Bank
may assign any or all of its rights under this Guaranty. In the event of any
such assignment, the Administrative Agent shall give Guarantor prompt notice of
same. If the Administrative Agent or any Bank elects to sell all the Loans or
participations in the Loans and the Loan Documents, including this Guaranty, the

                                        6
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Administrative Agent or any Bank may forward to each purchaser and prospective
purchaser all documents and information relating to this Guaranty or to
Guarantor, whether furnished by Borrower or Guarantor or otherwise, subject to
the terms and conditions of the Credit Agreement.

                  11.      Guarantor agrees, upon the written request of the
Administrative Agent, to execute and deliver to the Administrative Agent, from
time to time, any modification or amendment hereto or any additional instruments
or documents reasonably considered necessary by the Administrative Agent or its
counsel to cause this Guaranty to be, become or remain valid and effective in
accordance with its terms, provided, that, any such modification, amendment,
additional instrument or document shall not increase Guarantor's obligations or
diminish its rights hereunder and shall be reasonably satisfactory as to form to
Guarantor and to Guarantor's counsel.

                  12.      The representations and warranties of Guarantor set
forth in this Guaranty shall survive until this Guaranty shall terminate in
accordance with the terms hereof.

                  13.      This Guaranty contains the entire agreement among the
parties with respect to the subject matter hereof and supersede all prior
agreements relating to such subject matter and may not be modified, amended,
supplemented or discharged except by a written agreement signed by Guarantor and
the Administrative Agent.

                  14.      If all or any portion of any provision contained in
this Guaranty shall be determined to be invalid, illegal or unenforceable in any
respect for any reason, such provision or portion thereof shall be deemed
stricken and severed from this Guaranty and the remaining provisions and
portions thereof shall continue in full force and effect.

                  15.      This Guaranty may be executed in counterparts which
together shall constitute the same instrument.

                  16.      All notices, requests and other communications to any
party hereunder shall be in writing (including bank wire, telex, facsimile
transmission followed by telephonic confirmation or similar writing) and shall
be addressed to such party at the address set forth below or to such other
address as may be identified by any party in a written notice to the others:

If to Guarantor                     Equity Office Properties Trust
                                    Two North Riverside Plaza
                                    Suite 2100
                                    Chicago, Illinois 60606
                                    Attn: Chief Financial Officer
With Copies of
Notices to Guarantor to:            Equity Office Properties Trust
                                    Two North Riverside Plaza
                                    Suite 2100

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<PAGE>

                                    Chicago, Illinois 60606
                                    Attn: Chief Legal Counsel
                                            and
                                    Piper Rudnick LLP
                                    203 North LaSalle Street
                                    Suite 1800
                                    Chicago, Illinois 60601
                                    Attn:  James M. Phipps, Esq.
If to the
Administrative Agent:               JPMorgan Chase Bank
                                    270 Park Avenue
                                    New York, New York 10017
                                    Attn:  Marc Costantino
                                    Facsimile:  (212) 270-3513

                  EACH SUCH NOTICE, REQUEST OR OTHER COMMUNICATION SHALL BE
EFFECTIVE (i) IF GIVEN BY TELEX OR FACSIMILE TRANSMISSION, WHEN SUCH TELEX OR
FACSIMILE IS TRANSMITTED TO THE TELEX NUMBER OR FACSIMILE NUMBER SPECIFIED IN
THIS SECTION AND THE APPROPRIATE ANSWERBACK OR FACSIMILE CONFIRMATION IS
RECEIVED, (ii) IF GIVEN BY CERTIFIED REGISTERED MAIL, RETURN RECEIPT REQUESTED,
WITH FIRST CLASS POSTAGE PREPAID, ADDRESSED AS AFORESAID, UPON RECEIPT OR
REFUSAL TO ACCEPT DELIVERY, (iii) IF GIVEN BY A NATIONALLY RECOGNIZED OVERNIGHT
CARRIER, 24 HOURS AFTER SUCH COMMUNICATION IS DEPOSITED WITH SUCH CARRIER WITH
POSTAGE PREPAID FOR NEXT DAY DELIVERY, OR (iv) IF GIVEN BY ANY OTHER MEANS, WHEN
DELIVERED AT THE ADDRESS SPECIFIED IN THIS SECTION.

                  17.      Any acknowledgment or new promise, whether by payment
of principal or interest or otherwise by Borrower or Guarantor, with respect to
the Guaranteed Obligations shall, if the statute of limitations in favor of
Guarantor against the Administrative Agent shall have commenced to run, toll the
running of such statute of limitations, and if the period of such statute of
limitations shall have expired, prevent the operation of such statute of
limitations.

                  18.      This Guaranty shall be binding upon Guarantor and its
successors and assigns and shall inure to the benefit of the Administrative
Agent, the Syndication Agent, the Co-Documentation Agents, and the Banks and
their successors and permitted assigns.

                  19.      The failure of the Administrative Agent to enforce
any right or remedy hereunder, or promptly to enforce any such right or remedy,
shall not constitute a waiver thereof, nor give rise to any estoppel against the
Administrative Agent, nor excuse Guarantor from its obligations hereunder. Any
waiver of any such right or remedy to be enforceable against the Administrative
Agent must be expressly set forth in a writing signed by the Administrative
Agent.

                  20.      (a)      THIS GUARANTY AND THE RIGHTS AND OBLIGATIONS
OF THE PARTIES HEREUNDER SHALL BE CONSTRUED IN ACCORDANCE WITH AND

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<PAGE>

BE GOVERNED BY THE LAWS OF THE STATE OF NEW YORK.

                           (b)      Any legal action or proceeding with respect
to this Guaranty and any action for enforcement of any judgment in respect
thereof may be brought in the courts of the State of New York or of the United
States of America for the Southern District of New York, and, by execution and
delivery of this Guaranty, the Guarantor hereby accepts for itself and in
respect of its property, generally and unconditionally, the non-exclusive
jurisdiction of the aforesaid courts and appellate courts from any thereof. The
Guarantor irrevocably consents to the service of process out of any of the
aforementioned courts in any such action or proceeding by the mailing of copies
thereof by registered or certified mail, postage prepaid, to the Guarantor at
its address for notices set forth herein. The Guarantor hereby irrevocably
waives any objection which it may now or hereafter have to the laying of venue
of any of the aforesaid actions or proceedings arising out of or in connection
with this Guaranty brought in the courts referred to above and hereby further
irrevocably waives and agrees not to plead or claim in any such court that any
such action or proceeding brought in any such court has been brought in an
inconvenient forum. Nothing herein shall affect the right of the Administrative
Agent to serve process in any other manner permitted by law or to commence legal
proceedings or otherwise proceed against the Guarantor in any other
jurisdiction.

                           (c)      GUARANTOR HEREBY WAIVES ITS RIGHTS TO A JURY
TRIAL OF ANY AND ALL CLAIMS OR CAUSES OF ACTION BASED UPON OR ARISING OUT OF
THIS GUARANTY. IT IS HEREBY ACKNOWLEDGED BY GUARANTOR THAT THE WAIVER OF A JURY
TRIAL IS A MATERIAL INDUCEMENT FOR THE ADMINISTRATIVE AGENT TO ACCEPT THIS
GUARANTY AND THAT THE LOANS MADE BY THE BANKS ARE MADE IN RELIANCE UPON SUCH
WAIVER. GUARANTOR FURTHER WARRANTS AND REPRESENTS THAT SUCH WAIVER HAS BEEN
KNOWINGLY AND VOLUNTARILY MADE, FOLLOWING CONSULTATION WITH LEGAL COUNSEL. IN
THE EVENT OF LITIGATION, THIS GUARANTY MAY BE FILED BY THE ADMINISTRATIVE AGENT
IN COURT AS A WRITTEN CONSENT TO A NON-JURY TRIAL.

                           (d)      Guarantor does hereby further covenant and
agree to and with the Administrative Agent that Guarantor may be joined in any
action against Borrower in connection with the Loan Documents and that recovery
may be had against Guarantor in such action or in any independent action against
Guarantor (with respect to the Guaranteed Obligations), without the
Administrative Agent first pursuing or exhausting any remedy or claim against
Borrower or its successors or assigns. Guarantor also agrees that, in an action
brought with respect to the Guaranteed Obligations in any jurisdiction, it shall
be conclusively bound by the judgment in any such action by the Administrative
Agent (wherever brought) against Borrower or its successors or assigns, as if
Guarantor were a party to such action, even though Guarantor was not joined as a
party in such action.

                           (e)      Guarantor agrees to pay all reasonable
expenses (including, without limitation, attorneys' fees and disbursements)
which may be incurred by the

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<PAGE>

Administrative Agent or the Banks in connection with the enforcement of their
rights under this Guaranty, whether or not suit is initiated.

                  21.      Notwithstanding anything to the contrary contained
herein, this Guaranty shall terminate and be of no further force or effect upon
the full performance and payment of the Guaranteed Obligations hereunder and the
termination of the Commitments under the Credit Agreement. Upon termination of
this Guaranty in accordance with the terms of this Guaranty, the Administrative
Agent promptly shall deliver to Guarantor such documents as Guarantor or
Guarantor's counsel reasonably may request in order to evidence such
termination.

                  22.      All of the Administrative Agent's rights and remedies
under each of the Loan Documents or under this Guaranty are intended to be
distinct, separate and cumulative and no such right or remedy therein or herein
mentioned is intended to be in exclusion of or a waiver of any other right or
remedy available to the Administrative Agent.

                  23.      The Guarantor shall not use any assets of an
"employee benefit plan" within the meaning of Section 3(3) of ERISA or a "plan"
within the meaning of Section 4975(e)(1) of the Internal Revenue Code (the
"Code") to repay or secure the Loan, the Note, the Obligations or this Guaranty.
The Guarantor shall not assign, sell, pledge, encumber, transfer, hypothecate or
otherwise dispose of any of its rights or interests (direct or indirect) in
Borrower, or attempt to do any of the foregoing or suffer any of the foregoing,
or permit any party with a direct or indirect interest or right in Borrower to
do any of the foregoing, if such action would cause the Note, the Loan, the
Obligations, this Guaranty, or any of the Loan Documents or the exercise of any
of the Administrative Agent's, the Syndication Agent's, any Co-Documentation
Agent's, any Arranger's or Bank's rights in connection therewith, to constitute
a prohibited transaction under ERISA or the Code (unless the Guarantor furnishes
to the Administrative Agent a legal opinion satisfactory to the Administrative
Agent that the transaction is exempt from the prohibited transaction provisions
of ERISA and the Code (and for this purpose, the Administrative Agent, the
Syndication Agent, the Co-Documentation Agents, the Arrangers and the Banks, by
accepting the benefits of this Guaranty, hereby agree to supply Guarantor all
relevant non-confidential, factual information reasonably necessary to such
legal opinion and reasonably requested by Guarantor) or would otherwise result
in the Administrative Agent, the Syndication Agent, the Co-Documentation Agents,
or any of the Arrangers or Banks being deemed in violation of Sections 404 or
406 of ERISA or Section 4975 of the Code or would otherwise result in the
Administrative Agent, the Syndication Agent, the Co-Documentation Agents, or any
of the Arrangers or Banks being a fiduciary or party in interest under ERISA or
a "disqualified person" as defined in Section 4975(e)(2) of the Code with
respect to an "employee benefit plan" within the meaning of Section 3(3) of
ERISA or a "plan" within the meaning of Section 4975(e)(1) of the Code. The
Guarantor shall indemnify and hold each of the Administrative Agent, the
Syndication Agent, the Co-Documentation Agents, the Arrangers and the Banks free
and harmless from and against all loss, costs (including attorneys' fees and
expenses), expenses, taxes and damages (including consequential damages) that
each of the Administrative Agent, the Syndication Agent, the Co-Documentation
Agents, the Arrangers and the Banks may suffer by reason of the investigation,
defense and settlement of claims and in

                                       10
<PAGE>

obtaining any prohibited transaction exemption under ERISA necessary in
Administrative Agent's reasonable judgment as a result of Guarantor's action or
inaction or by reason of a breach of the foregoing provisions by Guarantor.

                  24.      This Guaranty shall become effective simultaneously
with the making of the initial Loans under the Credit Agreement.

                            [SIGNATURE PAGE FOLLOWS]

                                       11
<PAGE>

         IN WITNESS WHEREOF, the parties hereto have executed and delivered this
Guaranty as of the date and year first above written.

                                    GUARANTOR:
                                    EQUITY OFFICE PROPERTIES TRUST

                                    By:   /s/ Maureen Fear
                                        ______________________________
                                        Name:  Maureen Fear
                                        Title: Senior Vice President, Treasurer

ACCEPTED:

JPMORGAN CHASE BANK,
as Administrative Agent

By:    /s/  Marc E. Constantino
    _____________________
    Name:   Marc E. Constantino
    Title:  Vice President

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                          ACKNOWLEDGMENT FOR GUARANTOR

STATE OF ILLINOIS          )
                           ) SS.
COUNTY OF COOK             )

         On December 17, 2003, before me personally came Maureen Fear, to me
known to be the person who executed the foregoing instrument, and who, being
duly sworn by me, did depose and say that he is Sr VP & Treas, of Equity Office
Properties Trust, and that she executed the foregoing instrument in the
organization's name, and that he had authority to sign the same, and he
acknowledged to me that he executed the same as the act and deed of said
organization for the uses and purposes therein mentioned.

[Seal]

                                    /s/ Mary T. Van Derhaeqan
                                    ____________________________________
                                    Notary Public

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