To obtain a new compound having an N-succinimidyl aminocinnamate structure and enabling caged compounds useful for quantitatively measuring the concentration rise and fall of itself in a biosystem in a short time and also useful for observing succeeding various changes to be synthesized by a simple reaction.

This new compound is expressed by formula I [wherein X and Y are each H, a halogen or the like; R1 is H, a 1-4C alkyl or the like; R2 and R3 are each H, a 1-4C alkyl or the like and; Z is H or SO3M (wherein M is H, an alkali metal or an alkaline earth metal)] and is e.g. a compound of formula II. The compound of formula I is obtained by reacting 2- nitrobenzaldehyde with a Wittig reagent to form a cinnamate skeleton, by the hydrolysis of an ester group to form a carboxylic acid, by the condensation through dehydration of it with an N-hydroxysuccinimide to form an N- succipimidyl cinnamate and by reducing the nitro group substituent on the aromatic ring into an amino group.