Coumarins modified with dipeptides were prepared by condensation of N-hydroxysuccinimide esters of 2-(3,4,8-substituted-2-oxo-2 H-7-chromenyloxy)-and 2-(3,4-substituted-7-methyl-2-oxo-2 H-5-chromenyloxy)acetic and-propionic acids with amino acids and dipeptides.