Аннотация:Spectroscopic, luminescent, and spectral kinetic properties of cycloalkanone-based dienones and their diethylamino, methylthio, methoxy, and dimethoxy derivatives were studied. The presence of electron-donating substituents results in a red shift of the absorption and fluorescence spectral maxima. A laser pulse causes dienones to undergo intersystem crossing to the underlying triplet state with a lifetime of 0.2–40 μs as well as results in the formation of stable photoproducts capable of photoinduced conversion to the initial dienones. It also gives rise to intermediate products resulting from redox photoreactions of 2,4-bis(4-diethylaminobenzylidene)cyclobutanone in methanol in the presence of electron donor (ascorbic acid) and acceptor (para-nitroacetophenone) compounds.