Photophysics of two structurally similar dyes containing substituted amino as donor and carbonyl as acceptor groups

► Photophysical properties of two structurally similar dyes have been studied. ► Spectral parameters of the dyes have been found to be polarity sensitive. ► Both the dyes show similar optical response in neat and mixed binary solvents. ► Existence of two tautomeric forms upon addition of strong acid to the dye solution. ► The nature of emitting state in protic and aprotic media is different.