The paper presents spectral properties of six 3-substituted benzanthrone dyes dissolved. in ethanol. Absorption, fluorescence, photoacoustics and. time-resolved photothermal spectroscopy were used to follow radiative and non-radiative deactivation. pathways occurring in dyes with participation of their excited singlet and triplet states. Thermal deactivation parameters were evaluated. They show that global non-radiative deactivation of excited energy depends on a kind of peripheral groups attached to the main. molecular core. The yields of triplet state population and times of thermal deactivation decay were estimated and discussed in terms of the conformational changes in dyes and the differences in the dye molecular structures.