MORTGAGE, SECURITY AGREEMENT AND FIXTURE FILING
                                  Center Plaza
                              Boston, Massachusetts











                 MORTGAGE, SECURITY AGREEMENT AND FIXTURE FILING





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                                TABLE OF CONTENTS
                                -----------------

                                                                      Page

        1.     Payment of Indebtedness . . . . . . . . . . . .         11
        2.     Covenants of Title. . . . . . . . . . . . . . .         12
        3.     Usury . . . . . . . . . . . . . . . . . . . . .         12
        4.     Impositions . . . . . . . . . . . . . . . . . .         13
        5.     Tax Deposits. . . . . . . . . . . . . . . . . .         15
        6.     Change in Taxes . . . . . . . . . . . . . . . .         20
        7.     Insurance . . . . . . . . . . . . . . . . . . .         22
        8.     Insurance/Condemnation Proceeds . . . . . . . .         25
        9.      Restoration Following Fire and Other Casualty
                or Condemnation. . . . . . . . . . . . . . . .         28
       10.     Disposition of Condemnation or Insurance
                Proceeds . . . . . . . . . . . . . . . . . . .         37
       11.     Fire and Other Casualty; Self-Help. . . . . . .         40
       12.     Rent Insurance Proceeds . . . . . . . . . . . .         42
       13.     Intentionally Omitted . . . . . . . . . . . . .         42
       14.     Repair; Alterations; Waste; Environmental . . .         42
       15.     Environmental Indemnification . . . . . . . . .         52
       16.     Independence of Security  . . . . . . . . . . .         52
       17.     No Other Liens. . . . . . . . . . . . . . . . .         53
       18.     Management. . . . . . . . . . . . . . . . . . .         54
       19      Ground Lease  . . . . . . . . . . . . . . . . .         56
       20.     Sidewalks, Municipal Charges  . . . . . . . . .         56
       21.     Assignment of Rents and Leases  . . . . . . . .         57
       22.     Future Leases . . . . . . . . . . . . . . . . .         60
       23.     Mortgagor's Obligations as Lessor . . . . . . .         67
       24.     Leases; Foreclosure   . . . . . . . . . . . . .         69
       25.     Affiliate Subordinate Financing . . . . . . . .         69
       26.     Events of Default . . . . . . . . . . . . . . .         72
       27.     Remedies Upon Default . . . . . . . . . . . . .         85
       28.     Acceleration Interest . . . . . . . . . . . . .         91
       29.     Late Charge . . . . . . . . . . . . . . . . . .         92
       30.     Waiver of Statutory Rights. . . . . . . . . . .         93
       31.     Security Interest . . . . . . . . . . . . . . .         93
       32.     Right of Entry. . . . . . . . . . . . . . . . .         95
       33.     Estoppel Certificate. . . . . . . . . . . . . .         95
       34.     Annual Statements . . . . . . . . . . . . . . .         96
       35.     Rights Cumulative . . . . . . . . . . . . . . .         98
       36.     Subrogation . . . . . . . . . . . . . . . . . .         98
       37.     No Waiver . . . . . . . . . . . . . . . . . . .         99
       38.     Mortgage Extension. . . . . . . . . . . . . . .         99
       39.     Indemnification . . . . . . . . . . . . . . . .        100
       40.     Scope of Liability. . . . . . . . . . . . .            100
       41.     Attorneys' Fees . . . . . . . . . . . . . .            101
       42.     Administrative Fees . . . . . . . . . . . .            101
       43.     Protection of Security  . . . . . . . . . .            103
       44.     Notices . . . . . . . . . . . . . . . . . .            105
       45.     Release . . . . . . . . . . . . . . . . . .            106


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       46.     Applicable Law. . . . . . . . . . . . . . .            107
       47.     Invalidity. . . . . . . . . . . . . . . . .            107
       48.     Captions. . . . . . . . . . . . . . . . . .            107
       49.     Modifications . . . . . . . . . . . . . . .            108
       50.     Bind and Inure. . . . . . . . . . . . . . .            108
       51.     Replacement of Note . . . . . . . . . . . .            108
       52.     Time of the Essence . . . . . . . . . . . .            109
       53.     Statutory Condition; Statutory Power
                of Sale . . . . . . . . . . . . . . . . .             109


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Recording Requested By and
When Recorded Return to:

Nutter, McClennen & Fish
One International Place
Boston, MA  02110-2699
Attn:  Robert A. Fishman, Esq.



                 MORTGAGE, SECURITY AGREEMENT AND FIXTURE FILING



          THIS MORTGAGE is made as of the day of February, 1996, by CENTER PLAZA
ASSOCIATES LIMITED PARTNERSHIP, a Massachusetts limited partnership, having its
principal place of business at 50 Rowes Wharf, Boston, Massachusetts 02110
(hereinafter referred to as "Mortgagor") to CONNECTICUT GENERAL LIFE INSURANCE
COMPANY, a Connecticut corporation having its principal place of business at 900
Cottage Grove Road, Bloomfield, Connecticut 06002 (hereinafter referred to as
"Mortgagee").

                              W I T N E S S E T H:

          THAT, to secure (i) payment to Mortgagee of the principal indebtedness
of Sixty Million and No/100 Dollars ($60,000,000) together with interest
thereon, as evidenced by that certain promissory note (hereinafter referred to
as the "Note") of even date herewith, and any renewals, extensions or
modifications thereof (including, without limitation, any modification


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increasing the interest rate, the principal amount, the monthly payments or
extending the maturity date) given by Mortgagor to Mortgagee and made payable to
the order of Mortgagee, with the final payment being due and payable on March 1,
2003 (the "Maturity Date"), in and by which Note Mortgagor promises to pay the
said principal indebtedness and interest at the rate and in installments as
provided in the Note (the loan represented and evidenced by the Note is herein
referred to as the "Loan"), (ii) the performance of the covenants herein
contained and the payment of any monies expended by Mortgagee in connection
therewith, (iii) the payment of all obligations and the performance of all
covenants of Mortgagor under any other loan documents, agreements or instruments
between Mortgagor and Mortgagee given in connection with or related to this
Mortgage or the Note, and (iv) any and all additional advances made by Mortgagee
to protect or preserve the Security (hereinafter defined) or the security
interest created hereby on the Security, or for taxes, assessments, or insurance
premiums as hereinafter provided or for performance of any of Mortgagor's
obligations hereunder or for any other purpose provided herein (whether or not
the original Mortgagor remains the owner of the Security at the time of such
advances) [all of the aforesaid indebtedness and obligations of Mortgagor from
time to time outstanding being herein referred to as the "Indebtedness", and all
of the documents, agreements and instruments between Mortgagor and Mortgagee or
given by



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Mortgagor, Beacon Properties, L.P., a Delaware limited partnership ("BPLP"), or
CP Holding Corp., as Trustee of the Note Holding Trust under Indenture of Trust
dated as of November 30, 1994 ("NHT") in favor of Mortgagee, now or hereafter
evidencing or securing the repayment of, or otherwise pertaining to, the
Indebtedness, including, but not limited to the Environmental Indemnification
Agreement (defined and described in Section 15 hereof), the Intercreditor
Agreement (defined and described in Section 25 hereof), the Mortgage Assignment
(defined and described in Section 25 hereof), the BPLP Pledge (defined and
described in Section 25 hereof), the Mortgage Subordination (defined and
described in Section 25 hereof) and the Non-Recourse Guaranty (defined and
described in Section 25 hereof), being herein collectively referred to as the
"Loan Documents"], Mortgagor does hereby mortgage, grant with MORTGAGE
COVENANTS, bargain, sell, assign, pledge, transfer, and convey unto Mortgagee
and to Mortgagee's successors and assigns forever, all of the following
described land, improvements, real and personal property, rents and leases, and
all of its estate, right, title and interest therein (hereinafter collectively
called the "Security"):


          The land described in Exhibit A attached hereto and made a part
hereof, situate, lying and being in the City of Boston,



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County of Suffolk, and Commonwealth of Massachusetts (the
"Land");

          TOGETHER with all buildings and other improvements now or hereafter
located on said Land or any part thereof including but not limited to, all
extensions, betterments, renewals, renovations, substitutions and replacements
of, and all additions and appurtenances to, the Security (the "Improvements");

          TOGETHER with all of the right, title and interest of Mortgagor in and
to the land lying in the bed of any street, road, highway or avenue in front of
or adjoining the Land to the center lines thereof;

          TOGETHER with the right to use, in perpetuity, in connection with the
operation of the Security the names "Center Plaza", "One Center Plaza", "Two
Center Plaza" and "Three Center Plaza" and any other names similar thereto;

          TOGETHER with the benefit of and subject to those of the Permitted
Encumbrances (as hereinafter defined) listed in Part I of Exhibit B attached
hereto and made a part hereof, including, without limitation, all easements now
or hereafter located on or appurtenant to the Land and/or Improvements, or under
or above the same or any part thereof, and together with all rights-of-way


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and (to the extent assignable) all licenses, permits, approvals and privileges,
belonging or in any way appertaining to the Land and/or Improvements including
without limitation (i) any drainage ponds or other like drainage areas not
located on the Land which may be required for water run-off, (ii) any easements
necessary to obtain access from the Land to such drainage areas, or to any other
location to which Mortgagor has a right to drain water or sewage, (iii) any land
required to be maintained as undeveloped land by the zoning rules and
regulations applicable to the Land, and (iv) any easements and agreements which
are or may be established to allow satisfactory ingress to, egress from and
operation of the Land and/or the Improvements;

          TOGETHER with any and all awards hereafter to be made by any municipal
or other governmental authorities to the present and all subsequent owners of
the Security for the taking of all or any portion of the Security by power of
eminent domain, including, without limitation, awards for damage to the
remainder of the Security and any awards for any change or changes of grade of
streets affecting the Security, which said awards are hereby assigned to
Mortgagee, and Mortgagee, at its option, is hereby authorized, directed and
empowered (subject to Section 8 below) to collect and receive the proceeds of
any such awards from the authorities making the same and to give proper receipts
and acquittances therefor, and to apply the same in accordance with




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the applicable provisions of this Mortgage (all of the foregoing Land,
Improvements, rights, easements, rights-of-way, licenses, privileges, and
awards, collectively, the "Real Property");

          TOGETHER with all proceeds, insurance or otherwise, paid for the
damage done to any of the Security and all proceeds of the conversion,
voluntarily or involuntarily, of any of the Security into cash or liquidated
claims;

          TOGETHER with all fixtures, machinery, equipment, goods, and every
other article of personal property, tangible and intangible, now or hereafter
attached to or used in connection with the Real Property, or placed on any part
thereof and whether or not attached thereto, appertaining or adapted to the use,
management, operation or improvement of the Real Property, insofar as the same
and any reversionary right thereto may now or hereafter be owned or acquired by
Mortgagor (as more completely described in this paragraph and the next following
paragraph, the "Personal Property"), including, but without limitation: all
partitions; screens; awnings; shades; blinds; floor coverings; hall and lobby
equipment; heating, lighting, plumbing, ventilating, refrigerating,
incinerating, elevator, escalator, air conditioning and communication plants or
systems with appurtenant fixtures; vacuum cleaning systems; call systems;
sprinkler systems and other fire prevention and extinguishing


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apparatus and materials; all equipment, manual, mechanical and motorized, for
the construction, maintenance, repair and cleaning of, and removal of snow from,
parking areas, walks, underground ways, truck ways, driveways, common areas,
roadways, highways and streets; all equipment, manual, mechanical and motorized,
for the transportation of customers or employees to and from the facilities on
the Real Property; all telephone, computer and other electronic equipment and
appurtenances thereto, including software; and all other machinery, pipes,
poles, appliances, equipment, wiring, fittings, panels and fixtures; and any
proceeds therefrom, any replacements thereof or additions or accessions thereto;
all of Mortgagor's rights, but not Mortgagor's obligations, under Mortgagor's
leases for Personal Property; all contract rights held by Mortgagor from time to
time in existence of whatever nature relating to the Real Property or Personal
Property, including, but not limited to, architectural and engineering plans,
drawings, tests, reports or studies, contracts for goods or services and
management contracts, all warranties and guaranties under such contracts and
rights under insurance policies; all rights of Mortgagor under architect's
contracts, construction contracts, completion bonds, performance bonds and
payment bonds related to the Real Property or Personal Property; all accounts,
accounts receivable, parking garage revenues and receivables, contract rights,
general intangibles, documents, instruments and chattel paper arising from or in


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connection with the Real Property or Personal Property, including all books and
records in connection therewith and reserve accounts required to be established
now or at any time in the future under the Loan Documents, and all proceeds of
any and all of the same; all rights under all causes of action held by Mortgagor
related to the Real Property or Personal Property, including claims relating to
construction or the condition of the Improvements; all of Mortgagor's right,
title and interest in and to all artwork and sculpture located on the Real
Property; and all building materials, supplies and other property delivered to
the Real Property for incorporation into the Improvements thereon, all of which,
to the extent permitted by law, are declared to be a part of the realty and
covered by the lien hereof, but said lien shall not cover any fixture,
machinery, equipment or article of personal property which is owned by a tenant
and which can be removed from the Real Property by the tenant, but said lien
shall include any other fixture, machinery, equipment or article of personal
property incorporated into the improvements so as to constitute realty under
applicable law;

          TOGETHER with all of Mortgagor's books of account and records relating
to the Security, including all computers and software relating thereto;



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          TOGETHER with all contracts of sale and leases in the nature of a sale
of the Real Property, or any portion thereof, now and hereafter entered into and
all right, title and interest of Mortgagor thereunder, including, without
limitation, cash or securities deposited thereunder to secure performance by the
contract purchasers, which deposits Mortgagor may retain unless an Event of
Default (as hereinafter defined) exists hereunder; all licenses, permits,
franchises, governmental approvals and all sanitary sewer, drainage, water and
utility service agreements, reservations and capacities benefiting the Real
Property or any part thereof; and all rights of Mortgagor under any covenants,
agreements, easements, restrictions or declarations relating to, or as an
appurtenance to, the Real Property or the Personal Property or any part thereof;

          TOGETHER with all leases, subleases, licenses, concession agreements,
occupancy agreements or grants of other possessory interests now or hereafter in
force or effect, oral or written, and all renewals, extensions, modifications,
replacements and guaranties thereto affecting all or any part of the Land or
Improvements;

          TOGETHER with all rents, issues, revenues (including garage revenues),
profits and income from the Real Property and Personal Property;



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          TOGETHER with all of the right, title and interest of Mortgagor in and
to all and singular the tenements, hereditaments and appurtenances belonging to
or in any way pertaining to the Security; all the estate, right, title and claim
whatsoever of Mortgagor, either in law or in equity, in and to the Security; and
any and all other, further or additional title, estate, interest or right which
may at any time be acquired by Mortgagor in or to the Security, and if Mortgagor
shall at any time acquire any further estate or interest in or to the Security,
the lien of this Mortgage shall attach, extend to, cover and be a lien upon such
further estate or interest automatically without further instrument or
instruments, and Mortgagor, upon request of Mortgagee, shall execute such
instrument or instruments as shall reasonably be requested by Mortgagee to
confirm such lien, subject to the limitations on Mortgagor's liability set forth
in Section 40 below;

          TO HAVE AND TO HOLD the Security, and each and every part thereof,
unto Mortgagee and its successors and assigns forever, for the purposes and uses
herein set forth.

          AND, Mortgagor hereby further covenants, agrees and warrants (as
applicable) as follows:



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     1. Payment of Indebtedness. Mortgagor will pay the principal indebtedness
and interest thereon in accordance with the provisions of the Note and all
prepayment fees, late charges and fees required thereunder, and all extensions,
renewals, modifications, amendments and replacements thereof, and will keep and
perform all the covenants, promises and agreements, and pay all sums provided in
(i) each of the Note or any other promissory note or notes at any time hereafter
issued by Mortgagor to evidence the Indebtedness, (ii) this Mortgage, and (iii)
any and all other Loan Documents, all in the manner herein or therein set forth.
Subject to the limitations of liability set forth in Section 40 of this Mortgage
and Section 16 of the Note, Mortgagor shall be fully liable for such payment and
performance. If more than one corporation, partnership, trust, limited liability
company or other entity or person shall in the future execute this Mortgage as
Mortgagor or shall directly assume some or all of the obligations of Mortgagor
hereunder, whether as a result of a transfer of an interest in the Security
permitted by the Loan Documents, or otherwise as may be agreed to in writing by
Mortgagee, then each such entity and person shall be jointly and severally
liable for the satisfaction of all obligations and duties of Mortgagor under
this Mortgage, subject to the limitations of liability set forth in Section 40
of this Mortgage and Section 16 of the Note.




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     2. Covenants of Title. Mortgagor has good and indefeasible title to the
entire Real Property in fee simple, has absolute title to the Personal Property
(except as to personal property which is leased by Mortgagor, as to which
Mortgagor shall have good title to the lessee's interest under the leases), and
has good right and full power to sell, mortgage and convey the same; the
Security is free and clear of easements, restrictions, liens, leases and
encumbrances, except those easements, restrictions, liens, leases and
encumbrances listed on Exhibit B hereto or which may hereafter be created in
accordance with the terms hereof (the "Permitted Encumbrances"); and Mortgagor
will warrant and defend title to the Security against all claims and demands
whatsoever except the Permitted Encumbrances. The Permitted Encumbrances also
include leases and lease amendments hereafter entered into by Mortgagor in
accordance with Section 22 hereof. Mortgagee shall have the right, at its option
and at such time or times as it shall deem necessary, to take whatever action it
may deem necessary to defend or uphold the lien of this Mortgage or otherwise
enforce any of the rights of Mortgagee hereunder or any obligation secured
hereby, including without limitation, the right to institute appropriate legal
proceedings for such purposes.

     3. Usury. It is hereby expressly agreed that if from any circumstances
whatsoever fulfillment of any provision of the


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Note, this Mortgage, or any other Loan Documents, at the time performance of
such provision shall be due, shall involve transcending the limit of validity
presently prescribed by any applicable usury statute or any other law, with
regard to obligations of like character and amount, then ipso facto the
obligation to be fulfilled shall be reduced to the limit of such validity, so
that in no event shall any exaction be possible under the Loan Documents that is
in excess of the limit of such validity. In no event shall Mortgagor be bound to
pay for the use, forbearance or detention of the money loaned pursuant to the
Loan Documents, interest of more than the current applicable legal limit, if
any; the right to demand any such excess being hereby expressly waived by
Mortgagee.

     4. Impositions. Subject to the right of Mortgagor to contest an Imposition
(as hereinafter defined) as set forth below and subject to Section 5 below,
Mortgagor shall pay, before the last day on which the same may be paid without
penalty or interest, all real estate taxes, sewer rents, water charges,
municipal electric and all other municipal and governmental assessments, rates,
charges, impositions and liens (hereinafter referred to as "Impositions") which
now or hereafter are imposed by law upon the Security. Subject to the contest
rights hereinafter provided for, if any Imposition is not paid within the time
hereinabove specified, Mortgagee shall have the right to



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pay the same, together with any penalty and interest thereon, and the amount or
amounts so paid or advanced shall forthwith be payable by Mortgagor to Mortgagee
and shall be secured by the lien of this Mortgage; but Mortgagor may in good
faith contest, at Mortgagor's own cost and expense, by proper legal proceedings,
the validity or amount of any Imposition, on the condition that Mortgagor first
shall deposit with Mortgagee or a mutually satisfactory escrow agent pursuant to
a mutually satisfactory agreement, as security for the payment of such contested
item, an amount equal to the contested item plus all penalties and interest
which would be payable if Mortgagor is ultimately required to pay such contested
item (with due credit to Mortgagor for interest which will accrue on such
deposit if held by such escrow agent, Mortgagee hereby agreeing to permit such
escrow agent to invest the same at Mortgagor's direction in the investments
permitted under the Tax Escrow Agreement (as defined in Section 5 hereof) unless
an Event of Default exists hereunder, in which event Mortgagee shall direct such
investments), and on the further condition that no amount so contested may
remain unpaid for such length of time as shall permit the Security, or the lien
thereon created by the item being contested, to be sold for the nonpayment
thereof, or as shall permit an action of foreclosure or the like to be commenced
by the holder of any such lien. In the event that there is not an escrow agent,
any deposit required hereunder shall be deposited with Mortgagee to




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be held in a service account which is non-interest bearing to Mortgagor.
Mortgagor will not claim any credit on, or make any deduction from the
Indebtedness by reason of the payment of, any Imposition.

          Mortgagor hereby assigns to Mortgagee all rights of Mortgagor now or
hereafter arising in and to the refund of any Imposition and any interest
thereon. If at the time of receipt of any such refund by Mortgagee there exists
no Event of Default hereunder, then Mortgagee shall pay over the same to
Mortgagor promptly after demand; if there exists an Event of Default hereunder,
Mortgagee may apply said refund in reduction of the Indebtedness in whatever
order Mortgagee may elect.

      5. Tax Deposits. Mortgagor, Mortgagee and Fowler, Goedecke, Ellis &
O'Connor, Incorporated, as Escrow Agent, have entered into a certain Real Estate
Tax Escrow and Security Agreement of even date herewith, the terms of which
provide for the escrow and payments of money with respect to real estate taxes
(the "Tax Escrow Agreement"). Mortgagor covenants to perform its obligations
under the Tax Escrow Agreement, and Mortgagee hereby agrees that such
performance shall satisfy Mortgagor's obligations under this Mortgage with
respect to real estate taxes. In the event that Mortgagor shall default beyond
applicable grace periods under the Tax Escrow Agreement, or the


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Tax Escrow Agreement shall be terminated for any reason, or in the event that
the Tax Escrow Agreement becomes ineffective or otherwise unenforceable, then
the balance of the terms and conditions of this Section 5 shall be applicable
and control with respect to real estate taxes.

          Mortgagor shall deposit with Mortgagee or with an escrow agent
selected by Mortgagor and approved by Mortgagee (not to be unreasonably withheld
or delayed) pursuant to an escrow agreement reasonably acceptable to Mortgagee,
on the first day of the calendar month immediately following the date of this
Mortgage and on the first day of each calendar month thereafter (each of which
dates is hereinafter called the "monthly tax deposit date") until the payment in
full of the Indebtedness, a sum equal to one-twelfth of the real estate taxes,
assessments and any other Impositions which are required to be, or are
customarily, paid with real estate taxes or assessments (the "Qualified
Impositions") to be levied, charged, assessed or imposed upon or for the
Security within one year after said monthly tax deposit date. If on any monthly
tax deposit date the amount of Qualified Impositions to be levied, charged,
assessed or imposed within the ensuing one year period shall not be fixed, such
amount, for the purpose of computing the deposit to be made by Mortgagor
hereunder, shall be estimated by Mortgagee, with appropriate



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adjustment when the amount of such Qualified Impositions is
fixed.

          The sums deposited by Mortgagor under this Section shall be held in an
interest bearing account with interest being retained by Mortgagee and free of
trust, except as otherwise provided in the grammatical paragraph next following
and except to the extent, if any, that applicable law shall otherwise require,
and applied in payment of such Qualified Impositions when due (subject to
Mortgagor's contest rights set forth above). Mortgagor shall give fifteen (15)
days prior written notice to Mortgagee in each instance when a Qualified
Imposition is due, specifying the Qualified Imposition to be paid and the amount
thereof, the place of payment and the last day on which the same may be paid in
order to be within the time limit specified in Section 4 hereof entitled
"Impositions". Mortgagee shall not be responsible for any acts of or events
affecting the escrow agent nor shall Mortgagee have any obligation or liability
to Mortgagor if a different depository, or a different account with the selected
escrow agent, would or might pay a greater return on invested funds.

          Notwithstanding the foregoing provision, so long as Mortgagor holds
title to and controls the Security, Impositions are paid in full when due and
there exists no uncured default



                                                                         Page 17
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under the Loan Documents, notice of which has been given by Mortgagee to
Mortgagor, the interest earned by such escrows, less reasonable escrow costs,
will be paid to Mortgagor on each monthly tax deposit date; provided, however,
that interest shall be paid only if the escrow account is held by a mutually
agreed escrow agent and not by Mortgagee itself.

          If for any reason the sums on deposit with Mortgagee or escrow agent
under this Section shall not be sufficient to pay a Qualified Imposition within
the time specified in Section 4 hereof, then Mortgagor shall, within ten (10)
days after demand by Mortgagee, deposit sufficient sums so that Mortgagee may
pay such Qualified Imposition in full, together with any penalty and interest
thereon, subject to Mortgagor's contest rights set forth above. Mortgagee may
change its estimate of Qualified Impositions for any period, on the basis of a
change in an assessment or tax rate or on the basis of a prior miscalculation or
for any other bona fide reason communicated by Mortgagee to Mortgagor, in which
event Mortgagor shall deposit with Mortgagee or escrow agent within ten (10)
days after demand the amount of any excess of the deposits which would
theretofore have been payable under the revised estimate over the sums actually
deposited.



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          If any Qualified Imposition shall be levied, charged, assessed or
imposed upon or for the Security, or any portion thereof, and if such Qualified
Imposition shall also be a levy, charge, assessment or imposition upon or for
any other premises not covered by the lien of this Mortgage, then the
computation of the amounts to be deposited under this Section shall be based
upon the entire amount of such Qualified Imposition and Mortgagor shall not have
the right to apportion any deposit with respect to such Qualified Imposition.

          Upon an assignment of this Mortgage, Mortgagee shall have the right to
arrange to transfer all amounts deposited and still in its possession to the
assignee and, provided that the assignee assumes the obligations of Mortgagee
with respect to such amounts deposited, Mortgagee shall thereupon be completely
released from all liability with respect to such deposit and Mortgagor or the
owner of the Security shall look solely to the assignee or transferee in
reference thereto.

          Upon the payment in full by Mortgagor of the entire Indebtedness, any
sums then held by Mortgagee (or escrow agent) under this Section shall be
refunded to Mortgagor.

          All amounts deposited shall be held by Mortgagee as additional
security for the sums secured by this Mortgage, and



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Mortgagor hereby grants to Mortgagee a security interest in such sums, and upon
the occurrence of an Event of Default hereunder, Mortgagee may, in its sole and
absolute discretion, apply said amounts to the payment of the Indebtedness in
whatever order Mortgagee may elect.

          Immediately upon receipt of such by Mortgagor, Mortgagor shall deliver
to Mortgagee copies of all notices, demands, claims, bills, and receipts in
relation to the Qualified Impositions.

          Notwithstanding the foregoing provisions, Mortgagee hereby waives the
requirement for deposits as to that portion of Qualified Impositions payable
directly to the governmental or other authority by tenants under the terms of
leases approved by Mortgagee, provided satisfactory proof of payment is promptly
furnished to Mortgagee.

     6. Change in Taxes. In the event that, by reason of changes in law or in
the application or interpretation thereof, any tax (other than general income
taxes and similar taxes based on income) shall be due or become due and payable
to the United States of America, the Commonwealth of Massachusetts or any
political subdivision thereof with respect to the execution and delivery or
recordation of this Mortgage or any other Loan


                                                                         Page 20
<PAGE>


Document or the interest of Mortgagee in the Security, Mortgagor shall, subject
to Mortgagor's contest rights set forth in Section 4 above, which shall be
applicable hereto, mutatis mutandis, pay such tax at the time and in the manner
required by applicable law and Mortgagor shall hold Mortgagee harmless and shall
indemnify Mortgagee against any liability of any nature whatsoever as a result
of the imposition of any such tax. Notwithstanding the foregoing, in the event
that such tax shall be due or become due and payable as aforesaid in an amount
greater than $150,000 and if Mortgagee shall require Mortgagor to make payment
thereof or to indemnify Mortgagee as aforesaid, Mortgagor shall have the right
to prepay the Indebtedness in full, without paying a prepayment fee. If
Mortgagor is not permitted by law to make such payments, the Indebtedness shall,
at the option of Mortgagee, become due and payable upon one hundred eighty (180)
days notice without Mortgagor being obligated to pay a prepayment fee.
Notwithstanding the foregoing, Mortgagee shall not require Mortgagor to pay such
taxes or to indemnify Mortgagee as aforesaid, nor will Mortgagee exercise its
option to accelerate the Indebtedness pursuant to the preceding sentence, unless
it is the policy of Mortgagee to enforce such rights generally (meaning that,
over the course of numerous transactions, Mortgagee would more often than not
elect to enforce such rights) in connection with similar commercial mortgage
loans held by Mortgagee.



                                                                         Page 21
<PAGE>

     7. Insurance. Mortgagor shall, at all times until the Indebtedness shall be
paid in full, keep the Security insured against loss or damage for its full
replacement cost (which cost shall be reset once a year at Mortgagee's option)
under policies of so-called All Risk Replacement Cost Insurance with Agreed
Amount Endorsement (including risks of war and nuclear explosion, if available
at commercially reasonable rates), and shall further provide flood insurance (if
the Security is situated in an area which is considered a flood risk area by the
federal government or any agency thereof), boiler and machinery insurance,
earthquake insurance (if available at commercially reasonable rates), rent loss
insurance in an amount sufficient to cover the total of all rents accruing from
the Security for a one (1) year period, comprehensive general liability
insurance in a minimum amount of One Million Dollars ($1,000,000), and excess or
umbrella liability of at least Five Million Dollars ($5,000,000), and during any
period of restoration, a policy or policies of builder's "all risk" insurance in
an amount not less than the full insurable value of the Security against such
risks as Mortgagee may reasonably request, and such other appropriate insurance
as Mortgagee may reasonably require from time to time, in such amounts and with
such companies as shall be reasonably approved by Mortgagee with a Best's rating
of A:X or better (except to the extent Mortgagee, in its reasonable discretion,
approves a lower Best's rating upon Mortgagor's written request),




                                                                         Page 22
<PAGE>



and will deliver the original policy or policies of such insurance (or certified
duplicates thereof) to Mortgagee. Each such policy shall provide that the same
may not be cancelled or materially modified except upon thirty (30) days prior
written notice to Mortgagee, and shall otherwise be in such form as shall be
reasonably acceptable to Mortgagee, so that at all times until the payment in
full of the Indebtedness, Mortgagee shall have and hold the said policy and
policies (or certified duplicates thereof) as further collateral for the payment
of all Indebtedness. Each liability policy shall name Mortgagee as an
"additional insured"; and each other policy required to be maintained hereunder
(other than rent loss insurance) shall name Mortgagee as "loss payee" and
provide that all proceeds shall be payable to Mortgagee and that no act or thing
done by Mortgagor shall invalidate the policy as against Mortgagee, and shall be
endorsed with standard non-contributory mortgagee clauses and lender's loss
payee endorsements in favor of and in form reasonably acceptable to Mortgagee.
If Mortgagor shall fail to obtain any such policy or policies required by
Mortgagee, or shall fail to deliver the same (or certified duplicates thereof)
to Mortgagee, then Mortgagee may, after ten (10) days notice to Mortgagor (or
such shorter notice period as shall be appropriate if the policy is about to
expire), obtain such insurance and pay the premium or premiums therefor, in
which event Mortgagor shall, on demand of Mortgagee, repay such premium or
premiums to



                                                                         Page 23
<PAGE>



Mortgagee and such repayment shall be secured by the lien of this Mortgage.
Notwithstanding the foregoing, provided that such policies providing for such
coverages are in fact in effect (as evidenced by certificates thereof delivered
by Mortgagor to Mortgagee), and that Mortgagor has paid the premiums therefor,
Mortgagor shall not be required to deliver any such insurance policy (or a
certified duplicate thereof) to Mortgagee until the policy (or a certified
duplicate thereof) is delivered to Mortgagor by the insurer. Mortgagor covenants
to exercise reasonable efforts to secure delivery of such policies from the
insurer promptly after the policy has been underwritten and approved by the
insurer. If Mortgagor fails to maintain the level of insurance required under
this Mortgage, then Mortgagor shall indemnify Mortgagee to the extent that a
casualty occurs and insurance proceeds would have been available had such
insurance been maintained.

          Mortgagor shall promptly provide to Mortgagee copies of any and all
material notices (including notice of non-renewal and policy amendments),
claims, and demands which Mortgagor receives from insurers of the Security.

          Mortgagor hereby assigns to Mortgagee all rights of Mortgagor in and
to any unearned premiums on any insurance policy required to be furnished by
Mortgagor, which assignment may be


                                                                         Page 24
<PAGE>


exercised by Mortgagee at any time an Event of Default exists hereunder.

     8. Insurance/Condemnation Proceeds. Mortgagor hereby assigns to Mortgagee
all proceeds of any insurance or condemnation awards which Mortgagor may be
entitled to receive for loss or damage to, or a taking of, the Security. In the
event of loss or damage to, or a taking of, the Security, the proceeds of said
insurance or condemnation award shall be payable to Mortgagee alone and
Mortgagor hereby authorizes and directs any affected insurance company or
government agency to make payment of the insurance proceeds or condemnation
awards directly to Mortgagee; provided, however, if such proceeds or awards do
not exceed Three Hundred Thousand Dollars ($300,000), they shall be paid to
Mortgagor instead of Mortgagee for application by Mortgagor to the costs of
repair or restoration provided that there exists no uncured monetary default
under the Loan Documents and no uncured non-monetary default of which notice has
been given by Mortgagee to Mortgagor under the Loan Documents. In the event that
any such insurance proceeds or condemnation awards in excess of Three Hundred
Thousand Dollars ($300,000) are paid directly to Mortgagor, Mortgagor shall
deliver such proceeds or awards to Mortgagee within five (5) days of Mortgagor's
receipt thereof. No such loss or damage shall itself reduce the Indebtedness.
Unless an Event of Default exists hereunder,


                                                                         Page 25
<PAGE>


Mortgagor shall have the right, with Mortgagee's consent, which consent shall
not be unreasonably withheld or delayed, to adjust and compromise any loss or
damage; provided, however, that if such loss or damage does not exceed Three
Hundred Thousand Dollars ($300,000), and provided no Event of Default exists
hereunder, Mortgagor shall have the right to so adjust and compromise without
Mortgagee's consent. Subject to the provisions of Sections 9, 10, and 11 hereof,
such proceeds or awards shall be applied first toward reimbursement of all
reasonable costs and expenses of Mortgagee in collecting said proceeds or
awards, then toward payment of the Indebtedness or any portion thereof then
outstanding, in whatever order Mortgagee may elect, or Mortgagee may, at its
option, apply said insurance proceeds or condemnation awards in whole or in part
toward restoration of the Security for which such insurance proceeds or
condemnation awards shall have been paid. Any insurance proceeds or condemnation
awards received by Mortgagee on account of a loss or damage to, or taking of,
the Security shall, until the same are applied by Mortgagee as aforesaid, be
held by Mortgagee in an interest-bearing account, with all interest and other
income earned thereon to accrue to Mortgagor's benefit (except as set forth in
the next following sentence of this Section 8); and such proceeds or awards
shall be invested at Mortgagor's direction in the investments permitted under
the Tax Escrow Agreement, unless an Event of Default exists hereunder, in which
event Mortgagee


                                                                         Page 26
<PAGE>



shall direct such investments. Notwithstanding the foregoing, interest on such
proceeds and awards only shall be payable if Mortgagee and Mortgagor make
arrangements for a mutually acceptable third party to hold such proceeds and
awards and to invest the same pursuant to an agreement reasonably acceptable to
Mortgagee; if Mortgagee itself holds such proceeds and awards, Mortgagee shall
have no obligation to pay interest thereon. The income earned in respect of such
proceeds or awards shall be added thereto, and shall be held and applied by
Mortgagee in the same manner as provided for herein with respect to the proceeds
or awards themselves.

          In the event of foreclosure of this Mortgage or other transfer of
title to the Security in lieu of foreclosure, all right, title, and interest of
Mortgagor in and to any insurance policy, or premiums or payments of proceeds or
awards in satisfaction of claims or any other rights thereunder then in force,
shall pass to the purchaser or grantee notwithstanding the amount of any bid at
such foreclosure sale. Nothing contained herein shall prevent the accrual of
interest as provided in the Note on any portion of the principal balance due
under the Note until such time as the insurance proceeds or condemnation awards
are actually received and applied to reduce the principal balance outstanding.



                                                                         Page 27
<PAGE>



     9. Restoration Following Fire and Other Casualty or Condemnation. In the
event of damage to the Security by reason of fire or other hazard or casualty,
Mortgagor shall give prompt written notice thereof to Mortgagee and (subject to
the following provisions) shall proceed with reasonable diligence to perform
repair, replacement and/or rebuilding work (hereinafter referred to as the
"Work") to restore the Security to substantially its condition prior to such
damage in compliance in all material respects with all legal requirements,
provided that Mortgagee makes insurance proceeds available therefor. In the
event of a taking by power of eminent domain or conveyance in lieu thereof
("condemnation"), if restoration is feasible as reasonably determined by
Mortgagee, then Mortgagor (subject to the following provisions) shall proceed
with reasonable diligence to perform such restoration (also referred to as the
"Work"), provided that Mortgagee makes the condemnation awards available
therefor. Before commencing the Work, Mortgagor shall comply with the following
requirements if the cost of the Work exceeds Three Hundred Thousand Dollars
($300,000):

          a. Mortgagor shall furnish to Mortgagee complete plans and
specifications for the Work, for Mortgagee's approval, which approval shall not
be unreasonably withheld. Said plans and specifications shall bear the signed
approval thereof by an architect reasonably satisfactory to Mortgagee and shall
be



                                                                         Page 28
<PAGE>


accompanied by the architect's signed estimate, bearing the architect's seal, of
the entire cost of completing the Work.

          b. Mortgagor shall furnish to Mortgagee certified copies of all
permits and approvals required by law in connection with the commencement and
conduct of the Work.

          c. Mortgagor shall furnish to Mortgagee, prior to the commencement of
the Work, a surety bond for or guaranty of completion of and payment for the
Work, which bond or guaranty shall be in form satisfactory to Mortgagee and
shall be signed by a surety or sureties, or guarantor or guarantors, as the case
may be, who are reasonably acceptable to Mortgagee, and in an amount not less
than the architect's estimate of the entire cost of completing the Work, less
the amount of insurance proceeds or condemnation awards, if any, then held by
Mortgagee and which Mortgagee shall have elected or shall be required to apply
toward restoration of the Security as provided in Section 10 hereof.

          If the cost of the Work exceeds Three Hundred Thousand Dollars
($300,000), Mortgagor shall not commence any of the Work until Mortgagor shall
have complied with the above requirements, and thereafter Mortgagor shall
perform the Work diligently (subject to delays caused by events of force
majeure) and in good


                                                                         Page 29
<PAGE>



faith substantially in accordance with the plans and
specifications referred to in subsection (a) above.

          If, as provided in Section 10 hereof, Mortgagee shall have elected or
is required to apply any insurance proceeds or condemnation awards toward repair
or restoration of the Security, then so long as the Work is being diligently
performed (subject to delays caused by events of force majeure) by Mortgagor in
accordance with the provisions of this Mortgage, Mortgagee shall disburse such
insurance proceeds or condemnation awards to Mortgagor from time to time during
the course of the Work in accordance with the following provisions which shall
be applicable if the cost of the Work exceeds $300,000:

          A. The Work shall be in the charge of an experienced construction
manager reasonably satisfactory to Mortgagee with the consultation of an
architect or engineer, and before Mortgagor commences any Work, Mortgagee shall
have approved the plans and specifications for the Work to be submitted by
Mortgagor, it being nevertheless understood that, to the extent feasible, said
plans and specifications shall provide for such Work that, upon completion
thereof, the items being repaired or restored shall be at least equal in value
and general utility to their value and general utility prior to the damage,
destruction or condemnation;



                                                                         Page 30
<PAGE>


          B. Each request for payment shall not be made more often than at
thirty (30) day intervals, on seven (7) business days prior notice to Mortgagee,
and shall be accompanied by a certificate from an architect or engineer with
respect to items (i) and (iv) and a certificate from Mortgagor with respect to
items (ii), (iii), (v) and (vi), dated not more than ten (10) days prior to the
application for withdrawal of funds, stating:

               (i) that, to the best of its knowledge and belief, based upon
          diligent performance under its contract with Mortgagor in accordance
          with generally accepted standards of professional knowledge and skill,
          all of the Work for which payment is being requested is in place
          (except for materials stored off-site with Mortgagee's consent, which
          shall not be unreasonably withheld or delayed) and has been completed
          substantially in compliance with the approved plans and specifications
          and all applicable legal requirements;

               (ii) that the sum then requested to be withdrawn has been paid by
          Mortgagor and/or is justly due to contractors, subcontractors,
          materialmen, engineers, architects or other persons (whose names and
          addresses shall be stated) who have rendered or furnished certain
          services or materials for the Work and giving a brief

                                                                         Page 31
<PAGE>



          description of such services and materials and the principal
          subdivisions or categories thereof and the respective amounts so paid
          or due to each of said persons in respect thereof and stating the
          progress of the Work up to the date of said certificate;

               (iii) that the sum then requested to be withdrawn, plus all sums
          previously withdrawn, does not exceed the cost of the Work insofar as
          actually accomplished up to the date of such certificate and that the
          remainder of the monies held by Mortgagee will be sufficient to pay
          for the completion of the Work in full;

               (iv) that, to the best knowledge of such architect or engineer,
          the remainder of the moneys held by Mortgagee will be sufficient to
          pay in full for the completion of the Work;

               (v) that no part of the cost of the services and materials
          described in the foregoing paragraph (ii) of this Clause B has been or
          is being made the basis of the withdrawal of any funds in any previous
          or then pending application; and



                                                                         Page 32
<PAGE>


               (vi) that, except for the amounts, if any, specified in the
          foregoing paragraph (ii) of this Clause B to be due for services or
          materials, there is no outstanding indebtedness known, after due
          inquiry, which is then due and payable for work, labor, services or
          materials in connection with the Work which, if unpaid, might become
          the basis of a vendor's, mechanic's, laborer's or materialman's
          statutory or other similar lien upon the Security or any part thereof.

          C. Mortgagor shall deliver to Mortgagee reasonably satisfactory
evidence that the Security and every part thereof, and all materials and all
property described in the certificate furnished pursuant to the foregoing Clause
B, are free and clear of all mortgages, liens, charges or encumbrances, except
(a) encumbrances, if any, securing indebtedness due to persons (whose names and
addresses and the several amounts due them shall be stated) specified in said
certificate furnished pursuant to the foregoing Clause B, which encumbrances
will be discharged upon disbursement of the funds then being requested, and (b)
this Mortgage and the other Permitted Encumbrances. Mortgagee shall accept as
satisfactory evidence under this Clause C a certificate of a title insurance
company acceptable to Mortgagee or an endorsement to Mortgagee's existing loan
title policy



                                                                         Page 33
<PAGE>



      insuring the lien of this Mortgage, dated as of the date of the making of
      the disbursement, confirming the foregoing.

          D. Prior to the final disbursement, if Mortgagee reasonably requests,
Mortgagor shall deliver to Mortgagee a survey of the Security dated as of a date
within ten (10) days prior to the making of such disbursement showing no
encroachments other than those, if any, shown on the survey delivered to
Mortgagee contemporaneously with the execution and delivery of this Mortgage or
otherwise acceptable to Mortgagee.

              E. Prior to the first disbursement, Mortgagor shall deliver to
      Mortgagee, to Mortgagee's reasonable satisfaction, an opinion of counsel
      that the Security, if repaired, replaced and/or rebuilt in accordance with
      the approved plans and specifications, would comply with all applicable
      zoning, building, and similar land use laws, rules, and regulations.

          F. There exists no uncured monetary default under the Loan Documents
and no uncured non-monetary default notice of which has been given by Mortgagee
to Mortgagor under any of the Loan Documents.




                                                                         Page 34
<PAGE>



          Mortgagee at its option may waive any of the foregoing requirements.

          Upon compliance by Mortgagor with the foregoing Clauses A, B, C, D, E
     and F (except for such requirements, if any, as Mortgagee at its option may
     have waived), Mortgagor shall, to the extent of the insurance proceeds or
     condemnation award, if any, which Mortgagee shall have elected or shall be
     required to apply to restoration of the Security, pay or cause to be paid
     to the persons named in the certificate furnished pursuant to the foregoing
     Clause B, the respective amounts stated in said certificate to be due them
     less a retainage amount of 10% of the total contract price prior to 50%
     completion of the Work or such other retainage (or without retainage)
     ("Retainage") as shall be provided for in the applicable contract(s)
     approved by Mortgagee, which approval shall not be unreasonably withheld;
     and Mortgagee shall pay to Mortgagor the amounts stated in said certificate
     to have been paid by Mortgagor less Retainage.

          Upon completion of the Work, if the cost thereof exceeds Three Hundred
     Thousand Dollars ($300,000), in addition to the requirements of the
     foregoing Clauses A, B, C, D, E and F, Mortgagor shall promptly deliver to
     Mortgagee:




                                                                         Page 35
<PAGE>


          (a) A written certificate of the architect or engineer that the Work
     has been fully completed in a good and workmanlike manner substantially in
     accordance with the approved plans and specifications;

          (b) An endorsement to Mortgagee's title insurance policy reasonably
     acceptable to Mortgagee insuring the Security against mechanics' and
     materialmen's liens;

          (c) A certificate by Mortgagor in form and substance reasonably
     satisfactory to Mortgagee, listing all costs and expenses in connection
     with the completion of the Work and the amount paid by Mortgagor with
     respect to the Work; and

          (d) A temporary certificate of occupancy and all other applicable
     certificates, licenses, consents and approvals issued by governmental
     agencies or authorities with respect to the Security and (if obtainable) by
     the appropriate Board of Fire Underwriters or other similar bodies acting
     in and for the locality in which the Security is situated, provided further
     that within thirty (30) days after completion of the Work, Mortgagor shall
     obtain and deliver to Mortgagee a permanent certificate of occupancy for
     the Security or affected portions thereof.




                                                                         Page 36
<PAGE>





     Upon receipt of the foregoing items, Mortgagee shall pay any Retainage
still held by Mortgagee to Mortgagor.

     If upon completion of the Work there shall be insurance proceeds or
condemnation awards held by Mortgagee over and above the amounts withdrawn
pursuant to the foregoing provisions plus undisbursed Retainage, then, if an
Event of Default exists, Mortgagee may retain such proceeds or awards and apply
the same in reduction of the Indebtedness in whatever order Mortgagee may elect,
and if no Event of Default exists, Mortgagee shall pay over such proceeds or
awards to Mortgagor.

     10. Disposition of Condemnation or Insurance Proceeds. If such proceeds
exceed Three Hundred Thousand Dollars ($300,000), Mortgagee, in its absolute
discretion (except as hereinafter provided), may decide whether and to what
extent, if any, proceeds of insurance or condemnation will be made available to
Mortgagor for repair or restoration of the Security, but Mortgagor shall effect
such repair or restoration as set forth above provided Mortgagee makes such
proceeds available for that purpose. Notwithstanding the foregoing, Mortgagee
agrees to make insurance or condemnation proceeds available to Mortgagor for
repair or restoration provided:



                                                                         Page 37
<PAGE>



          (i)  The damage to the Improvements or the value of the taking does
               not exceed sixty percent (60%) of the replacement cost thereof,
               and, in the case of a condemnation, the portion of the Security
               not taken by condemnation has not, in Mortgagee's reasonable
               opinion, been rendered economically nonviable by the taking;

          (ii) There exists no uncured non-monetary default of which notice has
               been given by Mortgagee to Mortgagor and no uncured monetary
               default under the Note or any other Loan Documents;

         (iii) Mortgagor can demonstrate to Mortgagee's satisfaction that
               Mortgagor has the financial ability (through rent insurance or
               otherwise) to make all scheduled payments when due under the Loan
               Documents during repair or restoration;

          (iv) In the case of a casualty, the damage to the Real Property can be
               fully restored at least two months prior to the Maturity Date;

          (v)  In the case of condemnation, sufficient parking remains, and the
               operation of the Security will not, in



                                                                         Page 38
<PAGE>


               Mortgagee's reasonable opinion, be materially and adversely
               affected;

          (vi) The proceeds are released under the escrow/construction funding
               arrangements specified in Section 9 hereof;

         (vii) Annual income from leases in place and approved (or deemed
               approved) by Mortgagee (which will include, for purposes hereof,
               leases for which Mortgagee's approval is not required hereunder)
               that will survive restoration provide coverage of at least 1.40
               times the annual debt service (interest and, if applicable,
               principal) on the Loan; and

        (viii) The Work will return the Improvements to substantially the
               size, design, and utility as existed immediately before the
               casualty.

          If Mortgagee elects not to, and is not required to, make the proceeds
available for repair or restoration, then such proceeds shall be applied to
reduce the Indebtedness in whatever order Mortgagee may elect. Any application
of such proceeds to the principal indebtedness evidenced by the Note shall be at
par and shall cause a pro rata reduction in payments of interest and, if
applicable, principal, under the Note; provided, however, that



                                                                         Page 39
<PAGE>


if there exists an Event of Default, the prepayment fee as provided in the Note
shall also be due. Prepayment of the loan following Mortgagee's application to
principal reduction of insurance or condemnation proceeds shall be permitted
without payment of a prepayment fee, provided there then exists no Event of
Default under the Loan Documents and provided further that (i) such prepayment
must be made within one hundred eighty (180) days of Mortgagee's application to
principal reduction; (ii) Mortgagor keeps Mortgagee informed of its progress in
seeking replacement financing; and (iii) Mortgagor provides Mortgagee with
thirty (30) days advance notice of prepayment.

     11. Fire and Other Casualty; Self-Help. Subject to delays caused by events
of force majeure: If within one hundred eighty (180) days after the occurrence
of any damage to the Security or the condemnation of any portion of the Security
in excess of Three Hundred Thousand Dollars ($300,000), Mortgagor shall not have
submitted to Mortgagee for Mortgagee's approval the plans and specifications for
the Work, or shall not have obtained or be diligently seeking to obtain approval
of such plans and specifications from all governmental authorities whose
approval is required, or if, after such plans and specifications are approved by
Mortgagee and all such governmental authorities, Mortgagor shall fail to
promptly commence such Work, or if thereafter Mortgagor fails to perform the
Work diligently or is



                                                                         Page 40
<PAGE>



delinquent in the payment to mechanics, materialmen or others of the costs
incurred in connection with the Work (provided that Mortgagee shall have made
proceeds available therefor), or, if Mortgagor shall fail to complete the Work
promptly, then, in addition to all other rights herein set forth, and after
giving Mortgagor twenty (20) days written notice of the nonfulfillment of one or
more of the foregoing conditions and if such conditions remain uncured,
Mortgagee, or, following an Event of Default, any lawfully appointed receiver of
the Security, may at its option, perform or cause the Work to be performed, and
may take such other steps as it deems advisable to perform the Work, and may
enter upon the Security for any of the foregoing purposes, and Mortgagor hereby
waives (to the extent Mortgagor may lawfully do so) any claim against Mortgagee
or such receiver arising out of anything done by Mortgagee or such receiver
pursuant to this Section (other than claims arising by reason of the gross
negligence or willful misconduct of Mortgagee or such receiver) and Mortgagee
may apply insurance proceeds (without the need to fulfill the requirements of
Section 9 hereof) to pay for restoration costs or to reimburse Mortgagee and/or
such receiver for all amounts expended or incurred by them, respectively, in
connection with the performance of the Work, and any excess costs incurred by
Mortgagee shall be paid by Mortgagor to Mortgagee upon demand with interest at
the Default Rate (hereinafter



                                                                         Page 41
<PAGE>


defined) from the date of demand and such payment shall be secured by the lien
of this Mortgage.

     12. Rent Insurance Proceeds. If there shall be no Event of Default under
the Loan Documents, then all rent insurance proceeds shall be paid directly to
Mortgagor. If there exists an Event of Default, then such rent insurance
proceeds shall be paid to Mortgagee and may be applied by Mortgagee, at
Mortgagee's option, to the payment of the Indebtedness in whatever order
Mortgagee may elect.

     13. Intentionally Omitted.

     14. Repair; Alterations; Waste; Environmental. Mortgagor shall keep all of
the Security in good and substantial repair, subject to the provisions of
Section 9, to the extent applicable, and expressly agrees that it will neither
permit nor commit any waste upon the Security, nor do any act or suffer or
permit any act to be done to diminish the value of the Security or whereby the
lien hereof may be impaired. Mortgagor shall comply in all material respects
with all zoning laws, building codes, subdivision laws, environmental laws, and
other laws, ordinances, rules and regulations made or promulgated by any
government or municipality, or by any agency thereof or by any other lawful
authority, which are now or may hereafter become applicable to


                                                                         Page 42
<PAGE>


the Security, including but not limited to the Americans with Disabilities Act
of 1990 ("ADA"). Mortgagor shall use all reasonable efforts to cause tenants of
the Real Property to comply with their lease requirements regarding ADA. Without
limiting the foregoing, Mortgagor shall comply in all material respects (within
the time schedule set forth therein) with the ADA Compliance Plan, prepared by
Mortgagor, dated December 27, 1995, previously submitted to and approved by
Mortgagee. Mortgagor agrees not to initiate or acquiesce in any zoning variance
or reclassification, without Mortgagee's prior written consent. Mortgagor shall
not construct any additional building or buildings or make any other material
improvements on the Land nor alter, remove or demolish any building or other
Improvements on the Land in any material respect, without the prior written
consent of Mortgagee (which consent shall not be unreasonably withheld or
delayed), except for tenant improvement work in accordance with leases approved
(or deemed approved) by Mortgagee or which Mortgagee is not required to approve
pursuant to Section 22 of this Mortgage. Mortgagor shall at all times comply in
all material respects with any restrictive covenants applicable to the Security.
Mortgagor shall repair or restore any building now or hereafter under
construction on the Security and complete the same within a reasonable period of
time, subject to provisions of Section 9, to the extent applicable.





                                                                         Page 43
<PAGE>


          If Mortgagor suffers or permits any Event of Default to exist under
this Section 14, or in the event of an emergency, Mortgagee, or a lawfully
appointed receiver of the Security, following an Event of Default, at
Mortgagee's option and from time to time, may perform, or cause to be performed,
any and all repairs and such other work as it deems necessary to bring the
Security into compliance with the provisions of this Section and may enter upon
the Security for any of the foregoing purposes, and Mortgagor hereby waives (to
the extent Mortgagor may lawfully do so) any claim against Mortgagee and/or such
receiver arising out of such entry or out of any other act carried out pursuant
to this Section, except for claims arising out of the gross negligence or
willful misconduct of Mortgagee or such receiver. Mortgagor shall upon demand
repay to Mortgagee and such receiver, with interest at the Default Rate, from
the date of such demand, all amounts expended or incurred by them, respectively,
in connection with any action taken pursuant to this Section, and such repayment
shall be secured by the lien of this Mortgage.

          Mortgagor represents and warrants that there are and covenants that at
all times (except in the event of repairs or restoration, where temporary
limitations may occur) there will be located on the Real Property capacity for
the parking of at least 575 cars, which number may be subject to reduction (but
not below lease requirements) in the event that legal requirements



                                                                         Page 44
<PAGE>


applicable to the Real Property necessitate a reduction in such
capacity.

          Mortgagor represents and warrants that, except as disclosed to
Mortgagee in the Environmental Report (as defined and listed on Exhibit A to the
Environmental Indemnification Agreement, as defined in Section 15 hereof),
Mortgagor has not used and will not use and, to the best of Mortgagor's
knowledge, no prior owner or current or prior tenant, subtenant, or other
occupant of all or any part of the Security has used or is using Hazardous
Materials (hereinafter defined) on, from or affecting the Security in any manner
that violates the Environmental Laws (hereinafter defined); that, to the best of
Mortgagor's knowledge, except as set forth in the Environmental Report, no
Hazardous Materials have been disposed of on or migrated onto the Security in
violation of Environmental Laws and that Mortgagor will not permit or suffer any
such violation of the Environmental Laws.

          For purposes of this Mortgage, "Hazardous Materials" shall mean and
include those elements, materials, compounds, mixtures, wastes or substances
which are contained in the list of hazardous substances adopted by the United
States Environmental Protection Agency (the "EPA") or the Massachusetts
Department of Environmental Protection ("DEP") or any list of toxic pollutants



                                                                         Page 45
<PAGE>


designated by Congress or the EPA or DEP, or which are defined as hazardous,
toxic, pollutant, infectious, flammable or radioactive by any of the
Environmental Laws and whether or not included in such lists, shall be deemed to
include all elements, materials, compounds, mixtures, wastes and substances
containing petroleum, asbestos, chlorinated hydrocarbons, or polychlorinated
biphenyls ("PCB's").

     For purposes of this Mortgage, "Environmental Laws" shall mean and include
any Federal, Massachusetts or local statute, law, ordinance, code, rule,
regulation, order, or decree (i) regulating or relating to protection of human
health or the environment insofar as the same concern the Disposal (hereinafter
defined) of any Hazardous Materials, as now or at any time hereafter in effect,
or (ii) regulating or imposing liability or standards of conduct concerning the
Disposal of Hazardous Materials, as now or at any time hereafter in effect, or
both, including, without limitation, the Massachusetts Oil and Hazardous
Material Release Prevention and Response Act, as amended, M.G.L. C. 21E
("Chapter 21E"), the Massachusetts Hazardous Waste Management Act, as amended,
M.G.L. C. 21C, the Federal Comprehensive Environmental Response, Compensation
and Liability Act, as amended, 42 U.S.C. SS.9601 et. seq. ("CERCLA"), the
Superfund Amendments and Reauthorization Act, 42 U.S.C. SS.9601 et. seq., the
Federal Oil Pollution Act of 1990, 33 U.S.C.



                                                                         Page 46
<PAGE>


SS.2701, et. seq., the Federal Toxic Substances Control Act, 15 U.S.C.
SS.2601 et. seq., the Federal Resource Conservation and Recovery Act, as
amended, 42 U.S.C. SS.6901 et. seq., the Federal Hazardous Materials
Transportation Act, 49 U.S.C. SS.1801 et. seq., the Federal Clean Air Act, 42
U.S.C. S.7401 et. seq., the Federal Water Pollution Control Act, 33 U.S.C.
S.1251 et. seq., the River and Harbors Act of 1899, 33 U.S.C. SS.401 et.
seq., and all laws, statutes, rules, ordinances and regulations of the EPA, or
any other local, state or federal department, board, or agency, or any other
agency or governmental board or entity having jurisdiction over the Security, as
any of the foregoing have been, or are hereafter from time to time, amended,
reauthorized, replaced, supplemented or superseded.

          Mortgagor represents and warrants that, to the best of Mortgagor's
knowledge, except as set forth in the Environmental Report, no presence,
release, spill, transportation, migration, generation, treatment, processing,
storage, use, or disposal of any Hazardous Materials has occurred or is
occurring on, in, under, above or emanating from any portion of the Security by
any person or entity or other source, whether related or unrelated to Mortgagor,
in violation of any Environmental Law (collectively a "Disposal") and that
Mortgagor will not permit or suffer any such Disposal of Hazardous Materials on
the Security or permit any lien under Chapter 21E or CERCLA or any other
Environmental Law



                                                                         Page 47
<PAGE>



to attach to the Security or any portion thereof or interest therein. Mortgagor
represents and warrants that, except to the extent disclosed in the
Environmental Reports, it has not received any notice from the DEP (or its
predecessor, the Massachusetts Department of Environmental Quality Engineering),
the EPA or any other governmental agency or any tenant of the Security with
regard to such Hazardous Materials and has received no notice that the
environmental and ecological condition of the Security is in violation of any
Environmental Law.

          Mortgagor represents and warrants that, to the best of Mortgagor's
knowledge and belief, except as disclosed in the Environmental Report, the
Security does not contain any asbestos- containing material in friable form, and
there is no current airborne contamination of the Security by asbestos fiber.

          Mortgagor represents and warrants that, except as set forth in the
Environmental Report, it has not received any notice that the soil, surface
water, or ground water of or on the Security are not free from any spills of
Hazardous Materials, and Mortgagor has no knowledge of any such spill except as
set forth in the Environmental Report.

          Notwithstanding anything to the contrary contained in this Mortgage or
the Environmental Indemnification Agreement,



                                                                         Page 48
<PAGE>


Mortgagee acknowledges that during the ordinary course of office building and
parking garage operations, there are some Hazardous Materials that are being
used and stored on the Real Property by Mortgagor and Mortgagor's tenants.
Mortgagor hereby represents and warrants to Mortgagee that, to the best of its
knowledge, (i) such Hazardous Materials have not been used or stored in
violation of Environmental Laws in any material respect, and (ii) such Hazardous
Materials are present in quantities which are not known to pose a health or
safety hazard to occupants, employees or visitors to the Real Property or to any
adjacent property; and Mortgagor further covenants and agrees that no such
Hazardous Materials shall be allowed to be present on the Real Property other
than such ordinary use and incidental storage of Hazardous Substances as are
reasonably and customarily necessary for the regular and ordinary operation and
maintenance of the Real Property as a first-class office building and parking
garage, and in all events in compliance with applicable Environmental Laws.

          In the event that any investigation, site monitoring, containment,
clean-up, removal, restoration or other remedial work of any kind or nature (the
"Remedial Work") is required by any applicable Environmental Law, any judicial
order or by any governmental entity because of, or in connection with, the
current or future presence, suspected presence, release or suspected release of
a Hazardous Material in or about the air,



                                                                         Page 49
<PAGE>


soil, ground water, surface water or soil vapor at, on, about, under or within
the Security (or any portion thereof), Mortgagor shall within thirty (30) days
after written demand for performance thereof by Mortgagee (or such shorter
period of time as may be required under any applicable Environmental Law, court
order or governmental direction), commence and thereafter diligently prosecute
to completion, all such required Remedial Work so as to restore the Security to
compliance with all applicable Environmental Laws, court orders and governmental
directions. All such Remedial Work shall be performed by contractors approved
(which approval shall not be unreasonably withheld or delayed) in advance by
Mortgagee, and under the supervision of a consulting engineer approved (which
approval shall not be unreasonably withheld or delayed) by Mortgagee. All costs
and expenses of such Remedial Work shall be paid by Mortgagor including, without
limitation, Mortgagee's reasonable attorneys' fees, paralegal fees and costs
incurred in connection with monitoring or review of such Remedial Work. In the
event Mortgagor shall fail to timely commence and thereafter prosecute to
completion such Remedial Work, and such failure continues for thirty (30) days
after notice by Mortgagee to Mortgagor (or such shorter period of time as may be
required under any applicable Environmental Law, court order or governmental
direction or by the exigencies of the situation), Mortgagee may, but shall not
be required to, cause such Remedial Work to be performed and all



                                                                         Page 50
<PAGE>


costs and expenses thereof, or incurred in connection therewith, shall become
part of the Indebtedness.

          Mortgagor shall provide Mortgagee with prompt written notice (a) upon
Mortgagor's becoming aware of any alleged, suspected or actual Disposal of any
Hazardous Materials upon, in, under, or emanating from the Security in violation
of Environmental Laws; (b) upon Mortgagor's receipt of any notice from any
federal, state, municipal or other governmental agency or authority in
connection with any Hazardous Materials located upon, in, or under or emanating
from the Security; and (c) upon Mortgagor's obtaining knowledge of any
incurrence of expense by any governmental agency or authority in connection with
the assessment, containment or removal of any Hazardous Materials located upon,
in, or under or emanating from the Security.

          Mortgagor hereby authorizes Mortgagee and its agents and consultants
at any time and from time to time, upon reasonable advance notice to Mortgagor,
to enter upon the Security to conduct an environmental audit of the
Improvements, soils and ground water, including subsurface investigation, in the
event that Mortgagee has reason to believe that a Disposal of Hazardous
Materials in violation of any Environmental Laws has occurred or when a change
of or addition to the Environmental Laws makes inspection reasonable, the cost
of such audit to be added to the



                                                                         Page 51
<PAGE>


Indebtedness. Mortgagee shall provide Mortgagor with an estimate of the cost of
any such audit and shall conduct such audit in a manner intended to minimize
interference with the operations of the Security.

     15. Environmental Indemnification. Mortgagor and BPLP (collectively, the
"Indemnitors") have entered into an Environmental Indemnification Agreement of
even date herewith in favor of Mortgagee (the "Environmental Indemnification
Agreement"). The performance of the duties and obligations of the Indemnitors
under the Environmental Indemnification Agreement shall be part of the
Indebtedness secured by this Mortgage. Mortgagor's obligations under the
Environmental Indemnification Agreement are hereby incorporated into this
Mortgage by reference. Mortgagee's rights and remedies under the Environmental
Indemnification Agreement are intended to be in addition to and not in
substitution for any rights and remedies Mortgagee may have under this Mortgage
or as may generally be available to Mortgagee at law or in equity.

     16. Independence of Security. Mortgagor shall not by act or omission permit
any building or other improvement on any premises not subject to the lien of
this Mortgage to rely on the Security or any part thereof or any interest
therein to fulfill any municipal or governmental requirement, and Mortgagor
hereby



                                                                         Page 52
<PAGE>


assigns to Mortgagee any and all rights to give consent for all or any portion
of the Security or any interest therein to be so used. Similarly, no part of the
Security shall rely on any premises not subject to the lien of this Mortgage or
any interest therein to fulfill any governmental or municipal requirement.
Mortgagor shall not by act or omission impair the integrity of the Real Property
as a single zoning lot, and as one or more complete tax parcels separate and
apart from all other premises. Any act or omission by Mortgagor which would
result in a violation of any of the provisions of this Section shall be void.

     17. No Other Liens. Mortgagor shall not consent, agree to, or permit any
mortgage, lien, or security interest upon or affecting the Security or any part
thereof except as granted or permitted in this Mortgage and any other lien or
security interest granted to Mortgagee. Normal and customary equipment leases
and purchase money financing obtained to purchase new Personal Property, in
either case entered into in the ordinary course of Mortgagor's business, shall
not constitute a violation of the provisions of this Section 17.

          Mortgagor will, subject to Mortgagor's contest rights set forth in
Section 4 above, which shall be applicable hereto, mutatis mutandis, promptly
pay and discharge any and all amounts which are now or hereafter become liens
against the Security



                                                                         Page 53
<PAGE>


whether or not superior to the lien hereof or to any assignment
of rents and leases given to Mortgagee.

          Mortgagor will not, without the express prior written consent of
Mortgagee, conduct any business or acquire any properties except for business
and properties relating to the Security. Mortgagor is and shall at all times
while this Mortgage is in effect remain a single purpose entity, with its only
business being the ownership and operation of the Security. Mortgagor will not
incur any debt and will not guarantee the debt of any other person or party
except the Affiliate Subordinate Financing (as hereinafter defined),
indebtedness incurred pursuant to this Mortgage and any other unsecured
indebtedness incurred by Mortgagor to obtain funds to invest in the Security.

     18. Management. During the term of the loan secured hereby, the Security
shall at all times be operated and managed by an entity controlled by BPLP or an
entity approved by Mortgagee under a written management agreement approved in
advance in writing by Mortgagee and reasonably acceptable to Mortgagee in form
and substance. Mortgagee hereby approves Beacon Property Management, L.P. or
Beacon Property Management Corporation, each being an affiliate of BPLP, as
management agent for the Security. No change in such management (other than
substitution of Beacon Property Management, L.P. for Beacon Property Management



                                                                         Page 54
<PAGE>

Corporation, or visa versa) shall be made without the prior written approval of
Mortgagee, and any attempted change in management without Mortgagee's consent
shall be void. Mortgagee's approval of the management of the Security and the
terms of any management agreement shall not be unreasonably withheld,
conditioned or delayed. Any manager must have the expertise, competence and
capacity to manage first-class facilities such as the Real Property and have had
actual experience managing either at least (i) One Million (1,000,000) square
feet of similar office building space in the greater Boston area, or (ii) Two
Million (2,000,000) square feet of similar office building space in the United
States. Each management agreement relating to the Security (a) may not be
modified or amended in any material respect and any successor agreement may not
be entered into or any management company appointed (other than as permitted
above) without Mortgagee's prior written approval; and (b) must be
unconditionally subordinate by its terms to the lien of this Mortgage and
terminable upon foreclosure of this Mortgage (or a deed in lieu of foreclosure
of this Mortgage) without termination fee or penalty or other similar charge.

          The foregoing approval rights of Mortgagee also shall apply to the
management and operation of the parking garage. The parking garage shall not be
managed by a third party garage



                                                                         Page 55
<PAGE>


operator without Mortgagee's consent, not to be unreasonably withheld or
delayed. Mortgagee hereby approves Standard Parking as an acceptable third party
garage operator.

     19. Ground Lease. Mortgagor hereby represents and warrants to Mortgagee
that there exist no ground leases relating to or executed in connection with the
Security.

     20. Sidewalks, Municipal Charges. Mortgagor will promptly pay and discharge
any and all license fees and similar charges, with penalties and interest
thereon, which may be imposed by the municipality in which the Security is
situated, for the use of vaults, chutes, areas and other space beyond the lot
line and under or abutting the public sidewalks in front of or adjoining the
Security, and Mortgagor will promptly cure any violation of law and comply with
any order of such municipality respecting the repair, replacement or condition
of the sidewalk or curb in front of or adjoining the Security, and in default
thereof Mortgagee may, upon thirty (30) days notice to Mortgagor (or such
shorter notice period as may be required in order to comply with legal
requirements), pay any and all such license fees or similar charges, with
penalties and interest thereon, and the charges of the municipality for such
repair or replacement, and any amount so paid or advanced by Mortgagee and all
costs and expenses incurred in connection therewith (including, without
limitation,


                                                                         Page 56
<PAGE>



attorneys' fees), with interest thereon at the Default Rate from the date of
demand, shall be a demand obligation of Mortgagor to Mortgagee, and, to the
extent permitted by law, shall be added to the Indebtedness and shall be secured
by the lien of this Mortgage. The provisions of this Section 20 are subject to
Mortgagor's contest rights set forth in Section 4 above, which shall be
applicable hereto, mutatis mutandis.

     21. Assignment of Rents and Leases. As further security for the payment of
the Indebtedness, Mortgagor hereby presently, irrevocably, absolutely and
unconditionally transfers, assigns and sets over unto Mortgagee all of its
right, title and interest in and to all present and future leases, lease
termination agreements, license agreements, concession agreements, parking
management agreements and other occupancy agreements of any nature, oral or
written, of the Land and space in the Improvements, together with all
modifications, supplements, extensions, renewals and replacements thereof now
existing or hereafter made, and also together with the rights to sue for,
collect and receive all rents, prepaid rents, additional rents, royalties,
security deposits, damages payable upon default by tenant, or other sums in any
of said leases provided to be paid to the lessor thereunder, profits, income,
license fees, concession fees and issues of the Security (collectively,
"Rents"), to be applied by Mortgagee in payment of the



                                                                         Page 57
<PAGE>


Indebtedness and also together with any and all guaranties of the obligations of
the tenants thereunder and the rights of Mortgagor to receive, hold and apply
all bonds and security in all of said leases provided to be furnished to the
lessor thereunder, and also together with the rights of Mortgagor to enforce any
and all of the agreements, terms, covenants and conditions in all of said leases
provided and to give notices thereunder. Provided, however, that until an Event
of Default occurs hereunder, Mortgagor shall have a revocable license to collect
the Rents and to exercise and enjoy all of the aforesaid rights, privileges and
benefits. Mortgagee may receive and collect the Rents personally or through a
receiver upon the occurrence of an Event of Default, and during the pendency of
any foreclosure proceeding and during any redemption period. Upon the occurrence
of an Event of Default, Mortgagor agrees to consent to a receiver if this is
believed necessary or desirable by Mortgagee to enforce its rights under this
Section. Notwithstanding anything contained herein to the contrary, if all
outstanding Events of Default are subsequently cured or waived prior to
Acceleration of Maturity (as defined in the Note), then Mortgagor automatically
shall have the same revocable license to collect the Rents and enjoy all of the
aforesaid rights, privileges, and benefits.

          Mortgagor shall not otherwise assign or pledge, or contract, expressly
or by implication, to assign or pledge, any




                                                                         Page 58
<PAGE>


lease of the Land or space in the Improvements or the rights to sue for, collect
and receive any Rents, or the rights to receive, hold and apply any bonds and
security in any of said leases provided to be furnished to the lessor
thereunder, or the rights to enforce any of the agreements, terms, covenants or
conditions of said leases or to give notices thereunder, unless in each instance
the written consent thereto of Mortgagee be first obtained.

          Nothing in this Mortgage shall be construed to obligate Mortgagee,
expressly or by implication, to perform any of the covenants of Mortgagor as
lessor under any of the leases hereinabove assigned or to pay any sum of money
or damages therein provided to be paid by the lessor.

          If, notwithstanding the occurrence of an Event of Default, Mortgagee
shall from time to time suffer or permit Mortgagor to sue for, collect or
receive any Rents, or to receive, hold or apply any bonds or security under any
of the leases hereinabove assigned, or to enforce any of the agreements, terms,
covenants or conditions thereunder or to give notices under said leases, after
the occurrence of an Event of Default, neither such sufferance nor permission
shall constitute a waiver or relinquishment by Mortgagee of the rights hereunder
and hereby assigned to Mortgagee with respect to any subsequent Rents, or




                                                                         Page 59
<PAGE>



with respect to any subsequent receipt, holding or application of bonds or
security or any subsequent enforcement of such agreements, terms, covenants or
conditions or any subsequent notices; provided, however, notwithstanding the
foregoing, it is agreed by Mortgagee that if all outstanding Events of Default
are cured or waived prior to Acceleration of Maturity, then Mortgagor
automatically shall have the same revocable license to collect the Rents and to
otherwise deal with the leases as aforesaid.

     22. Future Leases. Mortgagor will not hereafter make any lease to any
tenant or amend, modify, terminate (except for termination for default by the
tenant and then only if the Real Property is still owned by Center Plaza
Associates Limited Partnership and no Event of Default exists hereunder), accept
surrender of, renew or extend any lease (other than a renewal or extension to
which a tenant is entitled under the terms of an existing lease or contained in
a lease that is subsequently approved or deemed approved by Mortgagee),
affecting the Security unless Mortgagee shall first consent thereto in writing,
which consent shall not be unreasonably withheld.

     Notwithstanding anything to the contrary contained herein, the aforesaid
approval requirements shall not apply with respect to (i) leases or amendments
to leases covering in each instance no more than 15,000 square feet of net
rentable area on the Real



                                                                         Page 60
<PAGE>

Property, or (ii) non-default lease terminations unapproved by Mortgagee with
respect to leases covering in each instance no more than 15,000 square feet of
net rentable area and aggregating not more than 45,000 net rentable square feet
per calendar year. A lease termination incident to relocation of tenants to
other space within the Real Property shall not count toward said 45,000 net
rentable square feet per calendar year, except that any net loss in occupied
space between the old space and the new space shall be counted. Further, if a
terminated tenant is replaced with other tenant(s) in substantially the same
premises within sixty (60) days of termination, such termination shall not count
toward said 45,000 net rentable square feet per calendar year if, and only if,
in Mortgagor's good faith judgment, the economic condition of the Real Property,
after giving effect to said particular replacement, remains the same or better
than the prior situation; provided, however, that any net loss in occupied space
between the terminated tenant and the new tenant(s) shall be counted.

     In addition, with respect to any new lease, amendment to lease or a
non-default lease termination as described in the immediately preceding
paragraph, all of the following conditions must be met:






                                                                         Page 61
<PAGE>

          (a) Mortgagor furnishes Mortgagee with certified copies of all such
     leases or amendments or terminations promptly following the execution of
     same by all the parties thereto, together with a detailed written breakdown
     of any and all costs to be incurred in connection therewith;

          (b) The Security must continue to be owned by Center Plaza Associates
     Limited Partnership;

          (c) Mortgagor shall not be in default under the Note, this Mortgage or
     any other Loan Document beyond any applicable grace or cure period;

          (d) All such leases or amendments or terminations must be entered into
     in the ordinary course of business, and all such leases or amendments must
     be (i) prepared and executed on the standard lease or amendment form
     approved by Mortgagee, and (ii) consistent with such approved lease or
     amendment form, except that minor and customary changes which do not
     materially affect the value of the lease or the protections and assurances
     granted to Mortgagee thereunder may be made;

          (e) Any such lease or amendment or termination must be with a bona
     fide arms-length third-party tenant (unaffiliated with Mortgagor or BPLP)
     and negotiated in good faith;

                                                                         Page 62
<PAGE>



          (f) No such lease or amendment shall provide an ownership interest in
     the Security to the tenant; and

          (g) Any such lease or amendment must comply with the New Lease and
     Amendment Requisites (defined hereinbelow).

     In circumstances where Mortgagee's prior consent is required to a lease,
lease amendment, termination or other leasing matter, Mortgagee's consent shall
be deemed to have been given unless, within ten (10) business days after
Mortgagee receives copies of the proposed lease, amendment or termination in
final form, together with the written breakdown of costs as required in clause
(a) above (or as to other matters, after Mortgagee's receipt of Mortgagor's
request for approval, together with supporting documentation or information, as
appropriate), Mortgagee advises Mortgagor of its disapproval and the grounds
therefor. Mortgagor's request for Mortgagee's approval under this Section 22
must be accompanied by a notice from Mortgagor highlighted in bold-faced capital
letters stating that Mortgagee's failure to respond within ten (10) business
days will result in Mortgagee's deemed approval as aforesaid. If Mortgagor fails
to provide such notice to Mortgagee, then the automatic approval provision
provided hereinabove shall not be applicable.



                                                                         Page 63
<PAGE>



          In addition to the foregoing, Mortgagor promptly shall furnish to
Mortgagee (i) progress drafts and letters of intent, if any, concerning proposed
leases, and (ii) copies of all default and/or termination notices which
Mortgagor gives to or receives from tenants.

          All future leases must expressly state that they are subordinate to
the lien of this Mortgage unless Mortgagee otherwise specifies. Unless otherwise
approved by Mortgagee, each future lease and each future amendment to leases
existing on the date hereof which extends the term by more than one (1) year
(other than pursuant to an extension or renewal option existing as of the date
hereof) must contain provisions that (i) upon notice to tenant by Mortgagee, the
lease shall become superior to the lien of the Mortgage, (ii) the tenant shall
attorn to any purchaser of the Real Property upon foreclosure of this Mortgage,
as amended from time to time, or in the event that a deed is given in lieu of
such foreclosure, and (iii) the tenant shall, upon receipt of notice from
Mortgagee under the separate Assignment of Rents and Leases given by Mortgagor
in favor of Mortgagee of even date herewith, commence paying its rents directly
to Mortgagee (collectively herein referred to as the "New Lease and Amendment
Requisites"). Notwithstanding the foregoing, with respect to future amendments
to leases existing on the date hereof, the New Lease and Amendment Requisites
need


                                                                         Page 64
<PAGE>



not be met if they are already contained in the lease or the tenant shall have
previously entered into an SNDA (as hereinafter defined) with Mortgagee with
respect to the same lease.

     Without limiting the foregoing, Mortgagee hereby reserves the right to
subordinate this Mortgage to any lease subsequently made by recording with the
Registry of Deeds in which this Mortgage is recorded a declaration to that
effect, executed by Mortgagee, which declaration once so recorded shall be
binding upon the tenant under such lease and its successors and assigns.
Mortgagee agrees, as to future leases and lease amendments, if requested to do
so by a tenant, to enter into a so-called subordination, non-disturbance and
attornment agreement ("SNDA"), on Mortgagee's standard form, with only such
changes as Mortgagee in its reasonable discretion agrees to (Mortgagee and
Mortgagor hereby agreeing with each other that they will each negotiate in good
faith with respect to changes to Mortgagee's standard form reasonably requested
by tenants), provided that Mortgagee shall have approved the lease or amendment
with such tenant.

          Mortgagor will furnish to Mortgagee a true and complete copy of each
lease, amendment, modification, extension, termination, or renewal of lease,
hereafter made by Mortgagor with respect to the Land or space in the Security,
within ten (10) days after delivery of each such lease, amendment,



                                                                         Page 65
<PAGE>



modification, extension, termination, or renewal by the parties thereto. After a
tenant takes occupancy, Mortgagor shall also furnish to Mortgagee a true and
complete copy of a letter agreement signed by such tenant confirming the
commencement date and expiration date of its lease, within ten (10) days after
execution and delivery thereof by such tenant and Mortgagor.

          Mortgagor will from time to time upon demand of Mortgagee, confirm in
writing the assignment to Mortgagee of any or all leases of the Land and space
in the Improvements, and such written confirmation shall be in substantially the
same form as the Assignment of Rents and Leases of even date herewith given by
Mortgagor to Mortgagee and as shall be necessary to make the same recordable.

     If Mortgagor receives an early termination fee from a tenant in excess of
$500,000 in connection with a lease termination agreement, then Mortgagor shall
deposit the entire fee into an interest-bearing escrow account to be established
with a mutually satisfactory escrow agent under a mutually satisfactory escrow
agreement, such escrowed funds to be released to Mortgagor (a) to pay for
leasing-related costs (e.g., tenant improvements, leasing commissions, space
planning, legal-leasing costs, and the like) and other capital improvements, and
(b) to the extent not used under (a) above, to reimburse Mortgagor ratably on a
monthly



                                                                         Page 66
<PAGE>



basis for the lost rent from the terminated lease. In addition to the foregoing,
if in any calendar year cumulative termination fees exceed $500,000, Mortgagor
shall deposit those fees in excess of $500,000 into an interest-bearing escrow
account described above. Until such escrow agent is selected, such funds shall
be held by an agent of Mortgagee in an interest-bearing account.

     23. Mortgagor's Obligations as Lessor. (a) Mortgagor shall, at Mortgagor's
cost and expense, perform in all material respects the obligations on the part
of the lessor to be performed pursuant to the terms of each and every lease or
letting, written or oral, now or hereafter made with respect to the Security or
any part or parts thereof, and shall not suffer or permit to exist any default
(beyond applicable notice and grace periods under said lease) in such
performance on the part of such lessor or permit any event to occur and continue
beyond the expiration of applicable notice and grace periods under the lease
which would give the tenant under any such lease the right to terminate the same
or to offset rent.

     (b) Mortgagor shall give Mortgagee immediate notice of the receipt by
Mortgagor of any notice of default from the tenant or its successors or assigns
under a lease, and Mortgagor shall furnish to Mortgagee promptly any and all
information which



                                                                         Page 67
<PAGE>



Mortgagee may request concerning the performance and observance of all material
covenants, agreements and conditions contained in the leases by the lessor
thereunder to be kept, observed and performed and concerning the compliance with
all terms and conditions of the leases. Mortgagor hereby authorizes Mortgagee
and its representatives, upon reasonable advance notice, to make investigations
and examinations concerning such performance, observance and compliance, and
Mortgagor, upon request, shall promptly deposit with Mortgagee any and all
documentary evidence relating to such performance, observance and compliance and
copies of any and all notices, communications, plans, specifications or other
instruments or documents received or given by Mortgagor in any way relating to
or affecting the leases which may concern or affect the estate of the lessor or
the tenant in or under the leases or in the premises thereby demised.

     (c) In the event of any failure by Mortgagor to keep, observe or perform
any covenant, agreement or condition contained in the leases or to comply with
the terms and conditions of the leases, which continues beyond the applicable
notice and grace period contained in the lease, any performance, observance or
compliance by Mortgagee pursuant to this Mortgage on behalf of Mortgagor shall
not remove or waive, as between Mortgagor and Mortgagee, the corresponding Event
of Default under the terms of this Mortgage.



                                                                         Page 68
<PAGE>



     24. Leases; Foreclosure. Any proceedings or other steps taken by Mortgagee
to foreclose this Mortgage, or otherwise to protect the interests of Mortgagee
hereunder, shall not operate to terminate the rights of any present or future
tenant of space in the Improvements, notwithstanding that said rights may be
subject and subordinate to the lien of this Mortgage, unless (subject to the
terms of any SNDA now or hereafter executed by and between Mortgagee and a
particular tenant) Mortgagee specifically elects otherwise in the case of any
particular tenant. The failure to make any such tenant a defendant in any such
foreclosure proceeding and to foreclose such tenant's rights will not be
asserted by Mortgagor or any other defendant in such foreclosure proceeding as a
defense to any proceeding instituted by Mortgagee to foreclose this Mortgage or
otherwise protect the interests of Mortgagee hereunder.

     25. Affiliate Subordinate Financing. Mortgagor has heretofore incurred
other indebtedness, in addition to the Indebtedness secured by, inter alia, this
Mortgage, which Mortgagor recognizes and agrees is expressly, absolutely and
unconditionally subordinate to the Indebtedness and which consists of the
following (herein collectively referred to as the "Affiliate Subordinate
Financing"): (i) A loan currently held by BPLP in the aggregate restated
principal amount of $61,000,000.00 (the "First Tier Loan") currently evidenced
by thirteen separate



                                                                         Page 69
<PAGE>


promissory notes, eleven of which are dated as of June 10, 1993 and two of which
are dated as of November 30, 1994 (collectively, the "First Tier Notes"), and
secured by the Subordinate Secured Loan Documents (defined hereinbelow); (ii) a
loan currently held by NHT in the restated principal amount of $48,060,479.50
(the "Second Tier Loan") currently evidenced by a promissory note executed on
November 30, 1994 and effective as of June 10, 1993 (the "Second Tier Notes")
and secured by the Subordinate Secured Loan Documents; and (iii) an unsecured
loan currently held by BPLP in the restated principal amount of $7,500,000.00
(the "Beacon Loan") currently evidenced by a promissory note dated as of June
10, 1993 (the "Beacon Note").

          The term "Subordinate Secured Loan Documents" as used herein shall
mean and include all instruments, documents and agreements evidencing, securing
or in any way relating to the First Tier Loan or the Second Tier Loan, or both,
including, but not limited to, each of the "Loan Documents" (as defined and
described in the Mortgage Assignment (as hereinafter defined and described)).

          Mortgagor acknowledges and agrees that, as a condition precedent to
Mortgagee agreeing to make the Loan to Mortgagor, the following transactions are
being implemented, and documents and agreements are being provided for the
benefit of Mortgagee,



                                                                         Page 70
<PAGE>


contemporaneously herewith: (A) Pursuant to a Subordination of Mortgage and Loan
Documents (the "Mortgage Subordination") of even date herewith, to be recorded
and filed herewith, BPLP has subordinated the Subordinate Secured Loan Documents
to this Mortgage and all of the other Loan Documents; (B) BPLP, NHT and
Mortgagee have entered into an Intercreditor and Subordination Agreement (First
and Second Mortgages) (the "Intercreditor Agreement") of even date herewith,
which addresses certain respective rights, covenants, obligations and remedies
of the parties thereto with respect to the Affiliate Subordinate Financing; (C)
pursuant to a Guaranty (the "Non-Recourse Guaranty") of even date herewith given
by BPLP to Mortgagee, BPLP has guaranteed the repayment of the Indebtedness to
Mortgagee, subject to the limitations on BPLP's liability set forth therein; (D)
pursuant to an unrecorded Assignment of Notes, Mortgage and Loan Documents and
Pledge Agreement (the "BPLP Pledge") of even date herewith by and between BPLP
and Mortgagee, BPLP has assigned and pledged to Mortgagee, inter alia, all of
BPLP's interest in the First Tier Loan and the Beacon Loan as collateral
security for the Non-Recourse Guaranty; and (E) pursuant to an Assignment of
Mortgage and Loan Documents (the "Mortgage Assignment") of even date herewith,
to be recorded and filed herewith, given by BPLP to Mortgagee, BPLP has assigned
to Mortgagee all of its right, title and interest in and to the Subordinate
Secured Loan Documents.



                                                                         Page 71
<PAGE>


          26. Events of Default. Each of the following shall constitute an
"Event of Default" hereunder and shall entitle the Mortgagee to exercise its
remedies hereunder and under any of the other Loan Documents or as otherwise
provided by law:

          (a) (i) Any payment of any installment of principal or interest due
     under the Note, or payment of any escrow deposits due under any of the Loan
     Documents, is not received by Mortgagee within five (5) business days
     following the date when such payment was due, (ii) any failure to pay the
     outstanding Principal Indebtedness (as defined in the Note) on the Maturity
     Date or when the maturity of the Note is accelerated in accordance with the
     terms of the Note, this Mortgage or any other Loan Document, or (iii) any
     failure in the performance of any payment obligation of Mortgagor under
     this Mortgage or under any other Loan Document, other than the obligations
     to make payments as described in clauses (i) and (ii) above, and such
     failure continues uncured for a period of ten (10) business days after
     Mortgagee gives written notice of such failure to Mortgagor;

          (b) If there shall be a failure by Mortgagor to perform any duty of a
     non-monetary nature under any of the Loan Documents, which failure to
     perform is not cured within thirty (30) days after written notice from
     Mortgagee to



                                                                         Page 72
<PAGE>


      Mortgagor of such failure to perform, except if such failure to perform is
      not susceptible of cure within such thirty (30)day period and Mortgagor
      commences to cure within such thirty (30) day period and thereafter
      diligently pursues such cure, then such cure period shall be extended for
      a reasonable period of time but in no event greater than one hundred
      twenty (120) days after such notice of failure to perform from Mortgagee
      to Mortgagor. Notwithstanding anything contained herein to the contrary,
      the notice and cure period provided under this clause (b) shall not be
      applicable to and shall not be in addition to any specific notice and cure
      or performance period provided under any other provision of this Section
      26, and the specific notice and cure or performance period provided for in
      such provision of this Section 26 shall control, and a failure by
      Mortgagor to cure a default under such provision of this Section 26 within
      the applicable cure period shall be an Event of Default under this
      Mortgage;

          (c) if an "Event of Default" occurs under the Note or under any other
     Loan Document (as defined therein);

          (d) Any representation, warranty or statement of Mortgagor or BPLP, as
     applicable, contained herein or in any of the other Loan Documents,
     including without limitation the


                                                                         Page 73
<PAGE>


      Environmental Indemnification Agreement, which is actually known by
      Mortgagor or BPLP, as applicable, to be untrue in any material respect as
      of the date when made;

          (e) Any representation, warranty, or statement of Mortgagor or BPLP,
     as applicable, contained herein or in any of the other Loan Documents,
     including without limitation the Environmental Indemnification Agreement,
     which is not actually known by Mortgagor or BPLP, as applicable, to be
     untrue in any material respect as of the date when made, but proves to be
     untrue in any material respect as of the date when made and remains untrue
     in any material respect for a period of thirty (30) days after Mortgagee
     gives Mortgagor a notice of default with respect thereto; provided,
     however, that if the nature of such representation, warranty or statement
     is such that the same cannot be made true in all material respects within
     such thirty (30) day period and any delay in Mortgagee's remedies would not
     (in Mortgagee's sole judgment) cause any material harm to Mortgagee or any
     of the Security, then the period required to make the same true in all
     material respects shall be extended, but in no event more than one hundred
     twenty (120) days in the aggregate, and such representation, warranty or
     statement shall not be deemed an Event of Default if Mortgagor shall within
     such thirty (30) day period commence to make the same true in all material



                                                                         Page 74
<PAGE>


      respects and thereafter diligently prosecute such cure to
      completion within the time period allowed;

          (f) Mortgagor, or a general partner of Mortgagor, if Mortgagor is a
     partnership, or any of Mortgagor's controlling shareholders (if Mortgagor
     shall in the future be a corporation), or any of Mortgagor's controlling
     members (if Mortgagor shall in the future be a limited liability company)
     or BPLP shall (i) file a petition or petitions seeking relief under Title
     11, United States Code, (ii) seek or consent to the appointment of a
     receiver or trustee for itself or for any of the Security, (iii) file a
     petition or petitions or initiate a proceeding or proceedings under the
     bankruptcy, insolvency, receivership, or similar laws of the United States,
     any state or any other jurisdiction, (iv) make a general assignment or
     assignments for the benefit of creditors, or (v) be generally unable to pay
     its debts as they mature;

          (g) A court shall enter an order, judgment or decree appointing,
     without the consent of Mortgagor, a receiver or trustee for it or for any
     of the Security or approving a petition filed against Mortgagor or against
     BPLP which seeks relief under the bankruptcy, insolvency, receivership or
     other similar laws of the United States, any state, or any



                                                                         Page 75
<PAGE>



     other jurisdiction, and such order(s), judgment(s) or decree(s) shall
     remain in force, undischarged or unstayed, for ninety (90) days after the
     entry thereof;

          (h) Mortgagor shall voluntarily encumber the Land or the Improvements
     with any lien other than the lien of this Mortgage and the Subordinate
     Secured Loan Documents;

          (i) The commencement of enforcement or foreclosure proceedings under
     any of the Affiliate Subordinate Financing by BPLP or NHT, or their
     successors or assigns (other than Mortgagee or its successors or assigns)
     with respect to the Security;

          (j) If BPLP or one of its affiliates (but not including, in any event,
     the current owner, NHT) acquires the Second Tier Notes and within twenty
     (20) days after written notice from Mortgagee to Mortgagor thereof fails to
     either (1) completely discharge all of the Affiliate Subordinate Financing,
     or (2) extend the maturity dates of the Second Tier Notes, the First Tier
     Notes and the Beacon Note until at least November 30, 2009;

          (k) If (1) BPLP or one of its affiliates (but not including, in any
     event, the current owner, NHT) acquires the


                                                                         Page 76
<PAGE>


     Second Tier Notes and (2) BPLP or one of its affiliates (but not including,
     in any event, the current owner, CP Holding Corp., a Massachusetts
     corporation, as Trustee of the Partnership Holding Trust under Indenture of
     Trust dated November 30, 1994 ("PHT")) acquires the partnership interest of
     PHT in Mortgagor, and within thirty (30) days thereof fails to completely
     discharge all of the Affiliate Subordinate Financing; and

          (l) A Transfer not expressly permitted under the provisions of this
     Section 26(l) shall occur without the prior written consent of Mortgagee. A
     "Transfer" shall mean the sale, mortgage, encumbrance, pledge, assignment
     or hypothecation or other transfer (collectively, "Dispositions") (i) of
     legal or beneficial title to the Security or any portion thereof, excluding
     the Permitted Encumbrances, (ii) of any direct or indirect legal or
     beneficial interest in any partner or member of Mortgagor, if Mortgagor is
     a partnership, joint venture, syndication, limited liability company or
     other group, or (iii) of a controlling interest in the stock of Mortgagor,
     if Mortgagor is a corporation; the liquidation or dissolution of Mortgagor
     or revocation or expiration of Mortgagor's charter shall also be deemed a
     Transfer.


                                                                         Page 77
<PAGE>


          Notwithstanding anything to the contrary herein contained, an
involuntary lien or encumbrance constituting a "Transfer" within the meaning set
forth above shall not be deemed a Transfer hereunder (1) if Mortgagor removes,
bonds or insures over the same to Mortgagee's reasonable satisfaction within
thirty (30) days after Mortgagor becomes aware of such lien or encumbrance and,
in any event, prior to the same being foreclosed upon by the party or parties
claiming such lien or encumbrance, or (2) if such involuntary lien or
encumbrance is being contested by Mortgagor in good faith and in accordance with
the provisions of Section 4 hereof, which shall be applicable to such
involuntary liens or encumbrances, mutatis mutandis.

          Notwithstanding anything to the contrary contained herein, Mortgagee
agrees that, so long as Mortgagor (i.e., Center Plaza Associates Limited
Partnership) holds title to the Security and there is no Event of Default under
the Loan Documents, the following Transfers shall be permitted without
Mortgagee's consent: (a) Transfers of interests in Mortgagor or in any partner
of Mortgagor to Beacon Affiliates (as hereinafter defined) shall be permitted
provided Mortgagor remains a "Domestic Entity" (i.e., a corporation, partnership
or other entity organized or formed under the laws of the United States of
America or any state thereof) domiciled in the United States of America; and (b)
Beacon (as hereinafter defined) (or Beacon's


                                                                         Page 78
<PAGE>


successors-in-interest as partners or members of Mortgagor or any partner of
Mortgagor, if applicable) shall be permitted to transfer from time to time all
or any part of its or their respective interests in Mortgagor or in any partner
of Mortgagor to a non-affiliate, provided that after each and every such
transfer is given effect: (x) a Beacon Affiliate continues to retain an
ownership interest in Mortgagor of greater than fifty percent (50%), (y)
Mortgagor remains a Domestic Entity domiciled in the United States of America,
and (z) BPLP or another Beacon Affiliate continues to be the managing general
partner or member of Mortgagor.

          For the purposes hereof, "Beacon" shall mean and include BPLP and/or
Beacon Properties Corporation, a Maryland corporation (the "Public REIT"); and a
"Beacon Affiliate" shall mean and include BPLP, the Public REIT and/or any other
entity which is at least 95% owned (directly or indirectly) by BPLP and/or the
Public REIT.

          Notwithstanding anything to the contrary contained herein, in no event
will any of the following Dispositions be prohibited or restricted under this
Mortgage: (x) Dispositions of stock interests in the Public REIT, (y)
Dispositions of limited partnership interests in BPLP, so long as the Public
REIT remains



                                                                         Page 79
<PAGE>


the sole general partner of BPLP, and (z) Dispositions of PHT's interest in
Mortgagor and of interests in PHT.

          Notwithstanding the provisions of this Section 26(l):

          A. Mortgagor shall have the right to transfer the Security to a Beacon
Affiliate or any other entity the ownership and control of which is held by the
same persons or entities which are permitted, under the preceding provisions of
this Section 26(l), to own and control Center Plaza Associates Limited
Partnership (a "Permitted Transferee"); provided that (I) no Event of Default
exists under the Loan Documents at the time of transfer; (II) the Permitted
Transferee is a Domestic Entity domiciled in the United States of America; (III)
the Permitted Transferee assumes the obligations of Mortgagor under the Loan
Documents, subject to the limitations on liability contained therein; and (IV)
Mortgagor shall pay for all of Mortgagee's reasonable costs and expenses
associated with the transfer, including, without limitation, attorneys' fees
charged by Mortgagee's staff counsel and outside special counsel. Upon such
transfer, any provision of this Mortgage which, by its terms, applies solely to
"Mortgagor" or "Center Plaza Associates Limited Partnership" shall also apply to
such Permitted Transferee. Following any such transfer, all the restrictions on
transfers of ownership interests in Center Plaza Associates Limited


                                                                         Page 80
<PAGE>



Partnership set forth in the preceding provisions of this Section 26(l) shall
apply to transfers of ownership interests in such Permitted Transferee.

          B. Mortgagor shall also have the right to a one-time sale, transfer or
assignment in whole or in part of its interest in the Security to any party of
equal qualification and credit- worthiness provided:

          (I)  there is no monetary default or non-monetary default, notice of
               which has been given by Mortgagee to Mortgagor, under the Loan
               Documents at the time of transfer;

          (II) a property inspection by Mortgagee or Mortgagee's designee shows
               that all reasonably necessary maintenance on or damage or
               destruction to the Real Property has been completed or repaired;

         (III) the proposed transferee shall be a Domestic Entity or citizen of
               the United States of America domiciled in the United States of
               America;

          (IV) the proposed transferee shall be a Qualified Real Estate Investor
               (as hereinafter defined) which is



                                                                         Page 81
<PAGE>


               a Domestic Entity or controlled by, or under common control with,
               a Qualified Real Estate Investor;

          (V)  the aggregate debt service coverage (based on Net Effective
               Rents, as hereinafter defined) on the Loan exceeds 1.50;

          (VI) the Qualified Real Estate Investor has specific related
               commercial real estate experience;

         (VII) the Qualified Real Estate Investor must own or manage a minimum
               of Two Million (2,000,000) square feet of Class A office space;

        (VIII) at least thirty (30) days prior to the transfer, Mortgagor must
               provide Mortgagee with all of the material provisions of such
               transfer including without limitation the proposed date of
               transfer, and the name, net worth, background and address of the
               proposed transferee and the purchase price;

          (IX) Mortgagor shall provide Mortgagee with such evidence as Mortgagee
               may reasonably require that



                                                                         Page 82
<PAGE>



               the proposed transferee shall assume and fulfill each and every
               obligation of Mortgagor under the Loan Documents and such
               transfer shall not affect or impair Mortgagee's security and
               rights under the Loan Documents;

          (X)  a non-refundable fee in the amount of one percent (1%) of the
               outstanding Principal Indebtedness shall be paid to Mortgagee at
               the closing of the transfer in cash or certified check to be
               retained by Mortgagee in order to induce Mortgagee to allow the
               proposed transferee to assume the obligations of Mortgagor under
               the Loan Documents;

          (XI) the loan-to-value ratio of the Loan based on a then current
               appraisal obtained at Mortgagor's expense and acceptable to
               Mortgagee must not exceed 70%;

          (XII) Mortgagor shall pay for all of Mortgagee's reasonable costs and
               expenses associated with the transfer, including, without
               limitation, attorneys' fees charged by Mortgagee's staff counsel
               and outside special counsel; and


                                                                         Page 83
<PAGE>



        (XIII) the Affiliate Subordinate Financing shall be discharged
               incident to the transfer.

          "Qualified Real Estate Investor" is defined as any reputable
corporation, partnership, joint venture, joint-stock company, trust or one or
more individuals which (x) shall have a minimum net worth of at least One
Hundred Fifty Million Dollars ($150,000,000), real estate assets of at least
Three Hundred Million Dollars ($300,000,000), and short-term liquid assets of at
least Ten Million Dollars ($10,000,000) and (y) if a foreign entity or
person(s), shall be represented by a domestic real estate advisor, and in any
case shall be free from any bankruptcy, reorganization or insolvency proceedings
or any criminal charges or proceedings in the United States of America or any
foreign country which would, in Mortgagee's reasonable judgment, raise a
material question as to the reputation of the investor or its ability to own and
to operate the Real Property and shall not have been, at the time of transfer or
in the past, an adverse party in any suit or proceeding brought against or by
Mortgagee. Mortgagee agrees to be reasonable in the review of such
qualifications.

          "Net Effective Rents" is defined as gross rent (including all rental
income for the twelve (12) month period immediately preceding the transfer)
minus operating expenses.



                                                                         Page 84
<PAGE>


     27. Remedies Upon Default. Immediately upon the occurrence of any Event of
Default, Mortgagee shall have the option, in addition to and not in lieu of or
substitution for all other rights and remedies provided in this Mortgage or any
other Loan Document or provided by law or in equity, and is hereby authorized
and empowered by Mortgagor, to do any or all of the following:

     (a) Declare without notice the entire unpaid amount of the Indebtedness
immediately due and payable and, at Mortgagee's option, (i) to bring suit
therefor, or (ii) to bring suit for any delinquent payment of or upon the
Indebtedness, or (iii) to take any and all steps and institute any and all other
proceedings in law or in equity that Mortgagee deems necessary to enforce
payment of the Indebtedness and performance of other obligations secured
hereunder and to protect the lien of this Mortgage.

     (b) Exercise the STATUTORY POWER OF SALE and commence foreclosure
proceedings against the Security, in a single parcel or in several parcels,
through judicial proceedings, by advertisement or as otherwise provided by law,
at the option of Mortgagee, pursuant to the statutes in such case made and
provided, and to sell the Security or to cause the same to be sold at public
sale, and to convey the same to the purchaser, in


                                                                         Page 85
<PAGE>



accordance with said statutes in a single parcel or in several parcels at the
option of Mortgagee.

     (c) Proceed against the Personal Property in accordance with Mortgagee's
rights and remedies with respect to the Personal Property including the right to
sell the Personal Property together with the Real Property or separately and
without regard to the remainder of the Security in accordance with the
Mortgagee's rights and remedies provided by the Massachusetts Uniform Commercial
Code as well as other rights and remedies available at law or in equity.

     (d) Cause to be brought down to date a title examination and tax histories
of the Security, procure title insurance or title reports or, if necessary,
procure new abstracts and tax histories; procure an updated or entirely new
environmental audit of the Security including building, soil, ground water and
subsurface investigations; have the Improvements inspected by an engineer or
other qualified inspector and procure a building inspection report; procure an
MAI or other appraisal of the Security or any portion thereof; enter upon the
Security at any time and from time to time to accomplish the foregoing and to
show the Security to potential purchasers and potential bidders at foreclosure
sale; make available to potential purchasers and potential bidders all
information obtained pursuant to the



                                                                         Page 86
<PAGE>



foregoing and any other information in the possession of Mortgagee regarding the
Security.

     (e) Either by itself or by its agent to be appointed by it for that purpose
or by a receiver appointed by a court of competent jurisdiction, as a matter of
strict right, without notice and without regard to the adequacy or value of any
security for the Indebtedness or the solvency of any party bound for its
payment, to take possession of and to operate the Security, Mortgagor hereby
waiving any right Mortgagor might have to object to or oppose any such
possession and, whether or not Mortgagee has taken possession of the Security,
to collect and apply the Rents, including those past due and unpaid, after
payment of all necessary charges and expenses, in reduction of the Indebtedness.
The receiver shall have all of the rights and powers permitted under the laws of
the Commonwealth of Massachusetts. Except for damage caused by Mortgagee's gross
negligence or willful misconduct, Mortgagor hereby waives any claim Mortgagor
may have against Mortgagee for mismanagement of the Security during Mortgagee's
operation of the Security under this subparagraph or as mortgagee in actual
possession under applicable statutes.

     (f) At its option without waiving any Event of Default, pay, perform or
observe any or all of Mortgagor's obligations



                                                                         Page 87
<PAGE>



under the Loan Documents, and all payments made or costs or expenses incurred by
Mortgagee in connection therewith shall be secured hereby and shall be, upon
demand, immediately repaid by Mortgagor to Mortgagee with interest thereon at
the Default Rate from the date of demand. Mortgagee shall be the sole judge of
the necessity for any such actions and of the amounts to be paid. Mortgagee is
hereby empowered to enter and to authorize others to enter upon the Security or
any part thereof for the purpose of performing or observing any such defaulted
term, covenant or condition without thereby becoming liable to Mortgagor or any
person in possession holding under Mortgagor, except for damage caused by
Mortgagee's gross negligence or willful misconduct.

     (g) Apply against the Indebtedness in such order as Mortgagee shall
determine any funds held for the benefit of Mortgagor in escrow by Mortgagee or
by any third-party escrow agent under any of the Loan Documents.

     Upon any foreclosure sale, Mortgagee may bid for and purchase the Security
and shall be entitled to apply all or any part of the Indebtedness as a credit
to the purchase price. In the event of any sale of the Security by foreclosure,
through judicial proceedings, by advertisement or otherwise, the proceeds of any
such sale which are applied in accordance with this Mortgage shall be applied in
the order following to: (i) all


                                                                         Page 88
<PAGE>



sums reasonably expended or incurred by Mortgagee in carrying out Mortgagor's
obligations under this Mortgage and any other Loan Documents, to the extent
Mortgagee is authorized to do so under the terms of this Mortgage or the other
Loan Documents, together with interest thereon as therein provided; (ii) all
accrued and unpaid interest upon the Indebtedness; (iii) the unpaid principal
amount of the Indebtedness; (iv) Foreclosure Costs (as hereinafter defined); and
(v) the surplus, if any, to the person or persons legally entitled thereto.

          Mortgagor will pay to Mortgagee upon demand all costs and expenses
incurred by Mortgagee upon the occurrence of an Event of Default in the exercise
of Mortgagee's rights and remedies under this Mortgage and the other Loan
Documents for collection of the Indebtedness, foreclosure on the Security or
otherwise, including without limitation title insurance fees and premiums,
environmental consultant's charges and appraisal, engineering and inspection
fees under Section 27(d), receiver's fees, costs and agent's compensation under
Section 27(e), auctioneer's fees and foreclosure sale advertising costs, any
deed excise tax stamps required to be affixed to the foreclosure deed and court
filing fees, together with attorneys' fees and costs which shall include without
limitation all attorneys' fees and costs incurred in connection with (A) the
exercise of Mortgagee's rights and remedies as aforesaid, (B) any negotiations,
other services and



                                                                         Page 89
<PAGE>



advice rendered regarding restructuring of the Indebtedness prior to any
foreclosure sale or deed in lieu of foreclosure, whether or not any such
restructuring or deed in lieu is actually accomplished, and (C) any petition
filed by or against Mortgagor under Title 11, United States Code. Any such
amounts incurred by Mortgagee shall be secured hereby and shall be immediately
repaid by Mortgagor to Mortgagee upon demand with interest thereon at the
Default Rate, from the date of demand, all of such amounts together with such
interest being collectively referred to as "Foreclosure Costs."

          Mortgagor hereby agrees that after a foreclosure sale, Mortgagor will
have no right to possess or remain upon the Security, Mortgagor acknowledging
Mortgagor's status as a trespasser in such circumstances.

          In the event of any acceleration of the Indebtedness pursuant to
paragraph (a) of this Section 27, Mortgagor shall pay to Mortgagee together with
the principal indebtedness and interest thereon an amount equal to the
prepayment fee provided for in the Note and such fee shall be included as part
of the Indebtedness.

          Failure to exercise any option to accelerate in the event of a default
or other circumstance permitting the exercise of



                                                                         Page 90
<PAGE>


such option, shall not constitute a waiver of the default or of the right to
exercise such option at a later time (so long as such default or other
circumstance continues to exist), or a waiver of the right to exercise such
option in the event of any other default or circumstance specified above.

     28. Acceleration Interest. In addition to any late payment charge which may
be due under the Note, Mortgagor shall pay interest on all sums due hereunder at
a rate (the "Default Rate") equal to the lesser of (i) the interest rate set
forth in the Note plus four percent (4%) per annum, or (ii) the maximum rate
permitted by law, from and after the first to occur of the following events: (A)
Mortgagee elects in writing to cause the acceleration of the Indebtedness; (B) a
petition under Title 11, United States Code, shall be filed by Mortgagor or if
Mortgagor shall seek or consent to the appointment of a receiver or trustee for
itself or for any of the Security, file a petition seeking relief under the
bankruptcy or other similar laws of the United States, any state or any other
jurisdiction, make a general assignment for the benefit of creditors, or is
generally unable to pay its debts as they become due; (C) a court shall enter an
order, judgment or decree appointing, with or without the consent of Mortgagor,
a receiver or trustee for it or for any of the Security or approving a petition
filed against Mortgagor which seeks relief under the bankruptcy or other similar
laws of the



                                                                         Page 91
<PAGE>



United States, any state or any other jurisdiction, and any such order, judgment
or decree shall remain in force, undischarged or unstayed, ninety (90) days
after it is entered; or (D) if all sums due hereunder are not paid on the
Maturity Date as set forth in the Note.

     29. Late Charge. In the event any sums due under the Note (exclusive of
principal due at maturity of the Note or by reason of the acceleration of the
Note), this Mortgage or any other Loan Document, are not paid by Mortgagor when
due, without regard to any cure or grace period, Mortgagor shall pay to
Mortgagee for the month during which such payment is not made when due and for
each month or fraction thereof that such sum remains unpaid, a late charge equal
to the lesser of four percent (4%) of such installment or the maximum amount
allowed by law, as the reasonable estimate by Mortgagee and Mortgagor of a fair
average compensation for the loss that may be sustained by Mortgagee due to the
failure of Mortgagor to make timely payments, and such amount shall be secured
hereby. Such late charge shall be paid without prejudice to the right of
Mortgagee to collect any other amounts provided to be paid or (if applicable) to
declare an Event of Default under this Mortgage or any other Loan Document.



                                                                         Page 92
<PAGE>


      30. Waiver of Statutory Rights. Mortgagor agrees, to the full extent
permitted by law, that upon an Event of Default hereunder, neither Mortgagor nor
anyone claiming through or under Mortgagor will set up, claim, or seek to take
advantage of any moratorium, reinstatement, forbearance, appraisement,
valuation, stay, homestead, extension, exemption or (after a sale by
foreclosure) redemption laws now or hereafter in force, in order to prevent or
hinder the enforcement or foreclosure of this Mortgage, or the sale of the
Security or the delivery of possession thereof immediately after such sale to
the purchaser at such sale, and Mortgagor, for itself and all who may at any
time claim through or under it, hereby waives to the full extent that it may
lawfully do so, the benefit of all such laws, and any and all rights to have the
assets subject to the security interest of this Mortgage marshalled upon any
foreclosure or sale under the power granted herein.

      31. Security Interest. This Mortgage shall, as to any equipment and other
Personal Property covered hereby, be deemed to constitute a security agreement,
and Mortgagor, as debtor, hereby grants to Mortgagee, as secured party, a
security interest therein pursuant to the Massachusetts Uniform Commercial Code.
Mortgagor agrees, upon request of Mortgagee, to furnish an inventory of Personal
Property owned by Mortgagor and subject to this Mortgage and, upon request by
Mortgagee, to execute any



                                                                         Page 93
<PAGE>


supplements to this Mortgage, any separate security agreement and any financing
statements and continuation statements in order to include specifically said
inventory of Personal Property or otherwise to perfect the security interest
granted hereby, subject always to the limitation of liability provided for in
Section 16 of the Note. Upon any Event of Default, Mortgagee shall have all of
the rights and remedies provided in said Code or otherwise provided by law or by
this Mortgage, including but not limited to the right to require Mortgagor to
assemble such Personal Property and make it available to Mortgagee at a place to
be designated by Mortgagee which is reasonably convenient to both parties, the
right to take possession of the Personal Property with or without demand and
with or without process of law and the right to sell and dispose of the same and
distribute the proceeds according to law. The parties hereto agree that any
requirement of reasonable notice shall be met if Mortgagee sends such notice to
Mortgagor at least ten (10) days prior to the date of sale, disposition or other
event giving rise to the required notice, and that the proceeds of any
disposition of any such Personal Property may be applied by Mortgagee first to
the reasonable expenses in connection therewith, including reasonable attorneys'
fees and legal expenses incurred, and then to payment of the Indebtedness. With
respect to the Personal Property that has become so attached to the Real
Property that an interest therein arises under the real property law of the
Commonwealth of



                                                                         Page 94
<PAGE>



Massachusetts, this Mortgage shall also constitute a financing statement and a
fixture filing under the Massachusetts Uniform Commercial Code. Mortgagor is the
record owner of the Real Property and the addresses of Mortgagor and Mortgagee
are as set forth on the first page of this Mortgage.

     32. Right of Entry. Mortgagee and Mortgagee's representatives may at all
reasonable times and without notice to Mortgagor if there exists an Event of
Default (otherwise, upon reasonable advance notice) enter upon the Security and
inspect the same, or cause it to be inspected by agents, employees or
independent contractors of Mortgagee, and show the same to others, but Mortgagee
shall not be obligated to make any such entry or inspection.

     33. Estoppel Certificate. Mortgagor, within fifteen (15) days after written
request from Mortgagee, will furnish a signed statement in writing, duly
acknowledged, of the amount then due or outstanding hereunder and, to the best
of its knowledge, whether or not any offsets or defenses exist against the
Indebtedness, and if so, specifying such offsets and defenses. Mortgagee, within
fifteen (15) days after written request from Mortgagor, will furnish a signed
statement in writing, duly acknowledged, of the amount then due and outstanding
hereunder and, to the best of its knowledge, whether or not any default


                                                                         Page 95
<PAGE>



exists under this Mortgage or any of the other Loan Documents, and if so,
specifying such default. Mortgagor shall, within fifteen (15) days following
Mortgagee's request, execute and deliver a current landlord estoppel certificate
with respect to the leases at the Security. If required by law or regulatory
authority, Mortgagor shall, upon Mortgagee's request, exercise any right it may
have to request an estoppel certificate from any or all of the tenants at the
Security; and, in such event, Mortgagee shall pay Mortgagor's reasonable costs
of preparing, requesting and negotiating such tenant estoppel certificates.

     34. Annual Statements. Mortgagor shall, within one hundred twenty (120)
days after the end of each fiscal year of Mortgagor, deliver to Mortgagee (a)
annual statements audited and certified (subject only to such qualifications as
are reasonably acceptable to Mortgagee) by Coopers & Lybrand or another
independent Certified Public Accountant reasonably satisfactory to Mortgagee,
together with any "Notes to Financial Statements" prepared by such accountant in
connection with such audit and certification, all prepared in accordance with
generally accepted accounting principles and showing in detail: (i) a balance
sheet for the Security as of the last day of such fiscal year; (ii) a statement
of earnings from the Security for such fiscal year showing, among other things,
all rents and other income therefrom and all expenses paid or incurred in
connection with the operation of the




                                                                         Page 96
<PAGE>



Security, and (iii) a statement of operating cash flows for the Security; and
(b) a statement signed by Mortgagor listing all leases of space in the
Improvements as of the last day of such fiscal year, the respective areas
demised thereunder, the names of the tenants, the respective expiration dates of
the leases, the respective rentals provided for therein, accounts receivable and
such other information as may reasonably be requested by Mortgagee. In addition,
Mortgagor agrees to provide Mortgagee with unaudited quarterly cash flow reports
and a current rent roll. Mortgagor also agrees to provide Mortgagee with a pro
forma income statement and current expense statement for the current and prior
calendar year by January 31 of the current year.

          If Mortgagor omits to prepare and deliver promptly any report required
by this Section, following notice and the expiration of the cure period provided
for in Section 26(b) hereof, Mortgagee may elect, in addition to exercising any
remedy for an Event of Default as provided for in this Mortgage, to make an
audit of all books and records of Mortgagor, including bank accounts, which in
any way pertain to the Security, and to prepare the statement or statements
which Mortgagor failed to procure and deliver. Such audit shall be made and such
statements shall be prepared by an independent Certified Public Accountant to be
selected by Mortgagee. Mortgagor shall pay all



                                                                         Page 97
<PAGE>



expenses of such audit and related services, which expenses shall be secured
hereby as part of the Indebtedness and shall be immediately due and payable upon
demand with interest thereon at the Default Rate from the date of demand.

          Mortgagee shall afford any information received pursuant to this
Section the same degree of confidentiality that Mortgagee affords similar
information proprietary to Mortgagee; provided, however, that Mortgagee does not
in any way warrant or represent that such information received from Mortgagor
will remain confidential; and, provided further, that Mortgagee shall have the
unconditional right to disclose, as necessary, any such information in the event
Mortgagee sells, transfers, conveys, or assigns the Mortgage or any portion of
the Indebtedness.

      35.     Rights Cumulative.  Each right and remedy of Mortgagee
under this Mortgage, the Note and the other Loan Documents shall
be in addition to every other right and remedy of Mortgagee and
such rights and remedies may be enforced separately or in any
combination.

     36. Subrogation. To the extent that proceeds of the Indebtedness are used
to pay any outstanding lien, charge or encumbrance affecting the Security, such
proceeds shall be deemed to have been advanced by Mortgagee at Mortgagor's
request, and



                                                                         Page 98
<PAGE>


Mortgagee shall be subrogated to all rights, interest and liens owned or held by
any owner or holder of such outstanding liens, charges and encumbrances,
irrespective of whether such liens, charges or encumbrances are released of
record; provided, however, that the terms and provisions hereof (including,
without limitation, Section 40 of this Mortgage) shall govern the rights and
remedies of Mortgagee and shall supersede the terms, provisions, rights, and
remedies under the lien or liens to which Mortgagee is subrogated hereunder.

     37. No Waiver. Any failure by Mortgagee to insist upon the strict
performance by Mortgagor of any of the terms and provisions hereof shall not be
deemed to be a waiver of any of the terms and provisions hereof, and Mortgagee,
notwithstanding any such failure, shall have the right thereafter to insist upon
the strict performance by Mortgagor of any and all of the terms and provisions
hereof to be performed by Mortgagor.

     38. Mortgage Extension. The lien hereof shall remain in full force and
effect during any postponement or extension of the time of payment of the
Indebtedness, or of any part thereof, and any number of extensions or
modifications hereof, of the Note or of any additional notes taken by Mortgagee,
shall not affect the lien hereof or the liability of Mortgagor or of any
subsequent



                                                                         Page 99
<PAGE>


obligor to pay the Indebtedness unless and until such lien or liability be
expressly released in writing by Mortgagee.

     39. Indemnification. Mortgagor shall indemnify and hold Mortgagee harmless
from and against all obligations, liabilities, losses, costs, expenses, fines,
penalties or damages (including attorneys' fees) which Mortgagee may incur by
reason of injury to persons or damage to property arising out of (i) tenant
improvement work or other construction work in or upon the Security by Mortgagor
or others claiming by, through or under Mortgagor, (ii) the operation or
maintenance of the Security by Mortgagor, or (iii) any other action or inaction
by, or matter which is the responsibility of, Mortgagor. Mortgagor shall defend
Mortgagee against any claim or litigation involving Mortgagee for the same, and
should Mortgagee incur such obligation, liability, loss, cost, expense, fine,
penalty or damage, then Mortgagor shall reimburse Mortgagee upon demand. Any
amount owed Mortgagee under this Section 39 shall bear interest at the Default
Rate from the date of demand therefor and shall be secured hereby.

     40. Scope of Liability. The provisions of Section 16 of the Note are hereby
incorporated by reference herein. As previously noted in Section 15 hereof, the
Indemnitors have executed a separate Environmental Indemnification Agreement to
reflect their




                                                                        Page 100
<PAGE>


liability for environmental matters regarding the Security, subject to the
limitations of liability set forth therein.

     41. Attorneys' Fees. Any reference to "attorney fees", "attorneys' fees",
or "attorney's fees" in this document includes but is not limited to both the
fees, charges and costs incurred by Mortgagee through its retention of outside
legal counsel and the allocable fees, costs and charges for services rendered by
Mortgagee's in-house counsel. Any reference to "attorney fees", "attorneys'
fees", or "attorney's fees" shall also include but not be limited to those
attorneys or legal fees, costs and charges incurred by Mortgagee in the
collection of any Indebtedness, the enforcement of any obligations hereunder,
the protection of the Security, the foreclosure of this Mortgage, the sale of
the Security in lieu of foreclosure, the defense of actions arising hereunder
and the collection, protection or setoff of any claim the Mortgagee may have in
a proceeding under Title 11, United States Code. Attorneys' fees provided for
hereunder shall accrue whether or not Mortgagee has provided notice of default
or of an intention to exercise its remedies for an Event of Default. All such
attorneys' fees, charges and costs shall be reasonable.

     42. Administrative Fees. Mortgagee shall have the right to charge
reasonable administrative fees during the term of the Note



                                                                        Page 101
<PAGE>


as Mortgagee may determine, in its reasonable discretion, in connection with any
servicing requests made by Mortgagor requiring Mortgagee's evaluation,
preparation and processing of any such requests. Administrative fees shall not
be charged for routine servicing matters contemplated by the Loan Documents
including, without limitation: processing payments; processing insurance and UCC
continuation documentation; processing escrow draws; review of tenant leases,
subordination, non-disturbance and attornment agreements and tenant estoppels on
standard forms approved by Mortgagee without material modifications. Such
administrative fees shall apply without limitation to requests for matters not
permitted or contemplated by the Loan Documents (including, without limitation:
requests for transfers or assignments, requests for partial releases; requests
for review of new easements), and to requests, which, while contemplated by the
Loan Documents, because of the nature of the request, will require significantly
more time than an institutional lender, acting reasonably, would contemplate for
such request (including without limitation, requests for the approval of tenant
leases, tenant estoppels and tenant subordination, non-disturbance and
attornment agreements which contain material differences from Mortgagor's or
Mortgagee's standard forms (including any standard changes approved by
Mortgagee, which for this purpose will be considered part of the standard
form)). Mortgagee shall also be entitled to reimbursement for professional fees
it incurs for



                                                                        Page 102
<PAGE>


such administration, including without limitation, those of architects,
engineers and attorneys' fees (whether (i) employed by Mortgagee or its
affiliate or (ii) engaged by Mortgagee or its affiliates as independent
contractors).

     43. Protection of Security; Costs and Expenses. Mortgagor shall appear in
and defend any action or proceeding purporting to affect the security hereof or
the rights or powers of Mortgagee, and shall pay all reasonable costs and
expenses, including without limitation cost of evidence of title and reasonable
attorneys' fees, in any such action or proceeding in which Mortgagee may appear,
and in any suit brought by Mortgagee to foreclose this Mortgage upon the
occurrence of an Event of Default or to enforce or establish any other rights or
remedies of Mortgagee hereunder upon the occurrence of an Event of Default. If
Mortgagor fails to perform any of the covenants or agreements contained in this
Mortgage, or if any action or proceeding is commenced which affects Mortgagee's
interest in the Security or any part thereof, including, but not limited to,
eminent domain, code enforcement, or proceedings of any nature whatsoever under
any federal or state law, whether now existing or hereafter enacted or amended,
relating to bankruptcy, insolvency, arrangement, reorganization or other form of
debtor relief, then if an Event of Default exists hereunder (or, if no Event of
Default exists hereunder, if Mortgagor fails, within




                                                                        Page 103
<PAGE>

thirty (30) days after notice by Mortgagee to Mortgagor [or such shorter notice
period as the exigencies of the situation may require], to take appropriate
action to correct such failure, etc., subject, however, to Mortgagor's contest
rights under this Mortgage, to the extent applicable) Mortgagee may, but without
obligation to do so and without further notice to or demand upon Mortgagor and
without releasing Mortgagor from any obligation hereunder, make such
appearances, disburse such sums and take such action as Mortgagee reasonably
deems necessary or appropriate to protect Mortgagee's interest, including, but
not limited to, disbursement of reasonable attorneys' fees, entry upon the
Security to make repairs or take other action to protect the security hereof,
and payment, purchase, contest or compromise of any encumbrance, charge or lien,
other than the Permitted Encumbrances, which in the judgment of Mortgagee
appears to be prior or superior hereto. Mortgagor further agrees to pay all
reasonable expenses of Mortgagee (including without limitation attorneys' fees
and disbursements) incident to the protection of the rights of Mortgagee
hereunder, or to enforcement or collection of payment of the Indebtedness,
whether by judicial or non-judicial proceedings, or in connection with any
bankruptcy, insolvency, arrangement, reorganization or other debtor relief
proceeding of Mortgagor, or otherwise in connection with an Event of Default.
Any amounts disbursed by Mortgagee pursuant to this Section shall be additional
indebtedness of Mortgagor secured by



                                                                        Page 104
<PAGE>


the Loan Documents as of the date of disbursement and shall bear interest at the
Default Rate from the date of demand therefor. All such amounts shall be payable
by Mortgagor immediately upon demand. Nothing contained in this Section shall be
construed to require Mortgagee to incur any expense, make any appearance, or
take any other action.

     44. Notices. Any notice, demand, request, statement or consent made
hereunder shall be in writing, signed by the party giving such notice, request,
demand, statement, or consent, and shall be delivered personally or delivered to
a reputable overnight delivery service providing a receipt addressed as set
forth below or to such other address within the continental United States of
America as theretofore may have been designated in writing by such party in
accordance with the terms of this Section 44. The effective date of any notice
given as provided in this Section shall be the date of personal service or one
(1) business day after delivery to such overnight delivery service, whichever is
applicable. As used herein, the phrase "business day" or "business days" shall
mean any calendar day(s) other than a Saturday, a Sunday or a Federal or a State
holiday on which the U.S. Postal Service offices are closed for business. For
purposes hereof, the addresses are as follows:

If to Mortgagee:     Connecticut General Life Insurance Company
                     c/o CIGNA Investments, Inc.



                                                                        Page 105
<PAGE>



                      900 Cottage Grove Road
                      Hartford, Connecticut  06152
                      Attn:  Investment  Services,  S-2313

With a copy to:       CIGNA Corporation
                      Investment Law Department
                      900 Cottage Grove Road
                      Hartford, Connecticut 06152-2215
                      Attn: Real Estate Division, S-215A


If to Mortgagor:      Center Plaza Associates Limited Partnership
                      c/o Beacon Properties Corporation
                      50 Rowes Wharf
                      Boston, Massachusetts 02110
                      Attn: Mr. Robert J. Perriello,
                            Chief Financial Officer

with a courtesy
copy to:              Goulston & Storrs
                      400 Atlantic Avenue
                      Boston, Massachusetts 02110-3333
                      Attn: Harold Stahler, Esq.


          Notwithstanding the foregoing agreement to provide courtesy copies,
such copies shall be courtesy copies only, and failure to provide such courtesy
copies shall have absolutely no effect or entitle Mortgagor to any remedy
whatsoever. Any notice duly given to Mortgagor shall be effective whether or not
the courtesy copies were given.

     45. Release. Upon the satisfaction in full of the Indebtedness, Mortgagee
shall release of record the Security from the lien hereof and from the lien of
any other Loan Document securing the indebtedness and shall surrender this
Mortgage, the other Loan Documents and all notes evidencing indebtedness



                                                                        Page 106
<PAGE>



secured by this Mortgage to Mortgagor. Mortgagor shall pay all costs of
recordation.

     46. Applicable Law. The provisions hereof shall be construed in accordance
with the laws of the Commonwealth of Massachusetts.

     47. Invalidity. If any provision of this Mortgage shall be held invalid or
unenforceable, the same shall not affect in any respect whatsoever the validity
of the remainder of this Mortgage, except that if such provision provides for
the payment of the Principal Indebtedness (as defined in the Note) and/or
interest payable under the Note or any escrow deposits payable under any of the
other Loan Documents, and such provision is rendered invalid or unenforceable in
a material respect, then Mortgagee may, at its option, declare the Indebtedness
due and payable upon one hundred eighty (180) days prior written notice to
Mortgagor and, provided there exists no Event of Default hereunder, without
prepayment fee.

     48. Captions. The captions in this instrument are inserted only as a matter
of convenience and for reference, and are not and shall not be deemed to be any
part hereof.


                                                                        Page 107
<PAGE>



     49. Modifications. This Mortgage may not be changed or terminated except in
writing signed by both parties. The provisions of this Mortgage shall extend and
be applicable to all renewals, amendments, extensions, consolidations, and
modifications of the other Loan Documents, and any and all references herein to
the Loan Documents shall be deemed to include any such renewals, amendments,
extensions, consolidations or modifications thereof.

     50. Bind and Inure. The provisions of this Mortgage shall be binding on
Mortgagor and its heirs, successors and assigns, and any subsequent owners of
the Security. The covenants of Mortgagor herein shall run with the land, and
this Mortgage and all of the covenants herein contained shall inure to the
benefit of Mortgagee, its successors and assigns.

     51. Replacement of Note. Upon receipt of evidence reasonably satisfactory
to Mortgagor of the loss, theft, destruction or mutilation of the Note, and in
the case of any such loss, theft or destruction, upon delivery of an indemnity
agreement reasonably satisfactory to Mortgagor or, in the case of any such
mutilation, upon surrender and cancellation of the Note, Mortgagor will execute
and deliver, in lieu thereof, a replacement note, identical in form and
substance to the Note and dated as of the date of the Note and upon such
execution and



                                                                        Page 108
<PAGE>



delivery all references in this Mortgage to the Note shall be deemed to refer to
such replacement note.

     52. Time of the Essence. Time is of the essence with respect to the intent,
meaning, construction and enforcement of each and every covenant, agreement and
obligation of Mortgagor under this Mortgage, the Note and the other Loan
Documents subject to any force majeure exceptions provided for thereunder.

     53. Statutory Condition; Statutory Power of Sale. This Mortgage is upon the
STATUTORY CONDITION for any breach of which, or upon the breach of any other of
Mortgagor's covenants and undertakings hereunder, in each case, following the
expiration of applicable notice and cure periods provided for in Section 26
hereof, Mortgagee shall have the STATUTORY POWER OF SALE.




                                                                        Page 109
<PAGE>



          IN WITNESS WHEREOF, Mortgagor has duly executed this Mortgage as a
sealed instrument on the day and year first above written.

                           MORTGAGOR:


                           CENTER PLAZA ASSOCIATES LIMITED PARTNERSHIP

                           By:   BCN Center Plaza, LLC,
                                 its General Partner

                                 By: Beacon Properties Corporation, a Member


                                      By:  /s/ Robert J. Perriello
                                           ------------------------------
                                           Name:  Robert J. Perriello
                                           Title: Senior Vice President


                                      By:  /s/ Nancy J. Broderick
                                           ------------------------------
                                           Name:  Nancy J. Broderick
                                           Title: Treasurer




                                                                        Page 110
<PAGE>

COMMONWEALTH OF MASSACHUSETTS

Suffolk, SS.                                                  February 9, 1996




     Then personally appeared Robert J. Perriello and Nancy J. Broderick, the
Senior Vice President and Treasurer, respectively, of the above-named Beacon
Properties Corporation, a Member of BCN Center Plaza, LLC, General Partner of
Center Plaza Associates Limited Partnership as aforesaid, and acknowledged the
foregoing instrument to be their free act and deed and the free act and deed of
Beacon Properties Corporation, BCN Center Plaza, LLC and Center Plaza Associates
Limited Partnership, before me.


                                        /s/ Deborah C. Rice
                                       -------------------------------------
                                       Notary Public
                                       My Commission Expires: April 13, 2001