Exhibit 4.1


 


	NUMBER	UNITS
	U-	 


 


SEE REVERSE FOR CERTAIN DEFINITIONS


 


CUSIP 601319 205


MILLSTREET CAPITAL ACQUISITION CORP.


 


UNITS CONSISTING OF ONE SHARE OF CLASS A
COMMON STOCK AND ONE-HALF OF 

ONE WARRANT,


EACH WHOLE WARRANT ENTITLING THE HOLDER TO
PURCHASE ONE SHARE OF CLASS A COMMON STOCK


 


THIS CERTIFIES THAT                     
is the owner of          Units.


 


Each Unit
(“Unit”) consists of one (1) share of Class A common stock, par value $0.0001 per share
(“Common Stock”), of Millstreet Capital Acquisition Corp., a Delaware corporation (the
 “Company”), and one-half of one redeemable warrant (the “Warrant”). Each
whole Warrant entitles the holder to purchase one (1) share (subject to adjustment) of Common Stock for $11.50 per share
(subject to adjustment). Each Warrant will become exercisable thirty (30) days after the Company’s completion
of a merger, capital stock exchange, asset acquisition, stock purchase, reorganization or other similar business combination with
one or more businesses (each a “Business Combination”) and will expire unless exercised before 5:00 p.m.,
New York City Time, on the date that is five (5) years after the date on which the Company completes its initial Business
Combination, or earlier upon redemption or liquidation (the “Expiration Date”). The Common Stock and
Warrants comprising the Units represented by this certificate are not transferable separately prior
to            , 2021, unless Seaport Global Securities LLC. elects to allow
separate trading earlier, subject to the Company’s filing of a Current Report on Form 8-K with the Securities and
Exchange Commission containing an audited balance sheet reflecting the Company’s receipt of the gross proceeds of the
Company’s initial public offering and issuing a press release announcing when separate trading will begin. The terms of
the Warrants are governed by a Warrant Agreement, dated as
of              , 2021, between the Company and Continental Stock
Transfer & Trust Company, as Warrant Agent, and are subject to the terms and provisions contained therein, all of which
terms and provisions the holder of this certificate consents to by acceptance hereof. Copies of the Warrant Agreement are on
file at the office of the Warrant Agent at 1 State Street, 30th Floor, New York, New York 10004, and are available
to any Warrant holder on written request and without cost.


 


This certificate is not valid
unless countersigned by the Transfer Agent and Registrar of the Company.


 


This certificate shall be
governed by and construed in accordance with the internal laws of the State of New York.


 


Witness the facsimile signature
of a duly authorized signatory of the Company.


 


	 	 	 	 	 
	Authorized Signatory	 	 	 	Transfer Agent


 






     


     


    

 





MILLSTREET CAPITAL ACQUISITION CORP.


 


The Company will furnish
without charge to each unitholder who so requests, a statement of the powers, designations, preferences and relative, participating, optional
or other special rights of each class of stock or series thereof of the Company and the qualifications, limitations, or restrictions of
such preferences and/or rights.


 


The following abbreviations,
when used in the inscription on the face of this certificate, shall be construed as though they were written out in full according to
applicable laws or regulations: 


 


	TEN COM     —      as tenants in common	 	UNIF GIFT MIN ACT	—	 	 	Custodian	 
	 	 	 	 	 	 	 	 
	TEN ENT       —     as tenants by the entireties	 	 	 	 	    (Cust)    	 	      (Minor)      
	 	 	 	 
	JT TEN        —    as joint tenants with right of survivorship and not as tenants in common	 	 	 	 	under Uniform Gifts to Minors Act
	 	 	 	 	 	 
	 	 	 	 	 	(State)


 


Additional abbreviations may also be used though
not in the above list.


 


For value received,                     
hereby sell, assign and transfer unto                     


 


(PLEASE INSERT SOCIAL SECURITY OR OTHER IDENTIFYING
NUMBER OF ASSIGNEE)


 


(PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING
ZIP CODE, OF ASSIGNEE)


 


Units represented by the within Certificate,
and do hereby irrevocably constitute and appoint


 


Attorney to transfer the said Units
on the books of the within named Company with full power of substitution in the premises.


 


Dated


 


	 	 
	 	 
	 	 
	 	Notice: The signature to this assignment must correspond with the name as written upon the face of the certificate in every particular, without alteration or enlargement or any change whatever.


 





	Signature(s) Guaranteed:	 
	 	 
	 	 
	THE SIGNATURE(S) MUST BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION (BANKS, STOCKBROKERS, SAVINGS AND LOAN ASSOCIATIONS AND CREDIT UNIONS WITH MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM, PURSUANT TO S.E.C. RULE 17Ad-15 (OR ANY SUCCESSOR RULE).	 




 


In each case, as more
fully described in the Company’s final prospectus dated                   ,
2021, the holder(s) of this certificate shall be entitled to receive a pro-rata portion of certain funds held in the trust account
established in connection with its initial public offering only in the event that (i) the Company redeems the shares of Class A
common stock sold in the Company’s initial public offering and liquidates because it does not consummate an initial business combination
within the time period set forth in the Company’s amended and restated certificate of incorporation, as the same may be amended
from time to time (such date being referred to herein as the “Last Date”), (ii) the Company redeems the shares of Class A
common stock sold in its initial public offering in connection with a stockholder vote to amend the Company’s amended and restated
certificate of incorporation to modify the substance or timing of the Company’s obligation to redeem 100% of the Class A common
stock if it does not consummate an initial business combination by the Last Date or with respect to any other provision relating to stockholders’
rights or pre-initial business combination activity, or (iii) if the holder(s) seek(s) to redeem for cash his, her or its
respective shares of Class A common stock in connection with a tender offer (or proxy solicitation, solely in the event the Company
seeks stockholder approval of the proposed initial business combination) setting forth the details of a proposed initial business combination.
In no other circumstances shall the holder(s) have any right or interest of any kind in or to the trust account.