The mixed monolayers of a photosensitive crown-ether (CE) and poly(maleic acid hexadecyl monoamide-alt-propylene) (P12) have been prepared and studied. Fluorescence spectra of CE have a strong band at 530-535 nm in solution (monomer) or at 593-603 nm in transferred monolayers (aggregates). Due to the interaction with poly mer the fluorescence maximum of CE is shifted to 530 nm in the mixed monolayers with P12.