The invention relates to new photolabile coumarinylmethyl esters of cyclic nucleotides of general formula I wherein R.sup.1 represents hydrogen, bromine or p-chlorophenylthio R.sup.4 represents 7-carboxymethoxy, 6,7-, 5,7- or 7,8-bis-(carboxymethoxy), 7-C.sub.1-C.sub.3-alkoxycarbonylmethoxy, 6,7-bis(C.sub.1-C.sub.3-alkoxycarbonylmethoxy), 5,7-bis(C.sub.1-C.sub.3-alkoxy-carbonylmethoxy), or 7,8-bis(C.sub.1-C.sub.3-alkoxycarbonylmethoxy), R.sup.2 represents --NH.sub.2 and R.sup.3 is hydrogen (adenine residue), or R.sup.2 represents --OH and R.sup.3 represents NH.sub.2 (guanine residue) The inventive compounds are biologically inactive and exhibit high solubility in aqueous buffer solutions, high efficiency in photocleavage and rapid kinetics of liberation, together with high resistance to solvolysis.