Аннотация:Fluorescence of the new crown-contg. styryl dyes and their complexes with Na cation was studied. The fluorescence quantum yield of the styryl dye increases during incorporation of the crown-ether substituent. Formation of the complex of crown-ether with a metal ion leads to the short-wave shift of the absorption and fluorescence bands, does not practically affect the fluorescence quantum yield of the dye in the absence of photoisomerization and increases the rate const. of the temp. fluorescence quenching. In the excited state the adiabatic change of the metal ion coordination in crown-cycle is possible. The trans-cis-photoisomerization of the styryl dyes and their metal complexes is a barrierless reaction.