The invention is a method for producing .delta.-aminopentadienoate derivatives of formula (1), the method comprising reacting a streptocyanine derivative of formula (2) with an ester derivative of formula (3) in the presence of an organic base. In formulae (1) to (3), R.sup.1 represents an alkyl group or an aryl group; R.sup.2, R.sup.3, R.sup.4 and R.sup.5 independently represent a hydrogen atom or an alkyl group; R.sup.2 and R.sup.3, or R.sup.4 and R.sup.5 may bond to each other to form a ring; Y represents an electron attractive group; X represents an acid radical; n indicates 0 or a positive number, which is no more than 5; Y may bond to R.sup.1 to form a ring ##STR00001##