It is shown that excitation of solutions of 2-naphthaldehyde in either cyclohexane or acetonitrile at 300 K with light of 308-nm wavelength leads in both cases to the formation of two triplet states which have slightly different lifetimes T in the range 250 < T < 350 ns. These triplet states, formed monophotonically by excitation with an excimer laser pulse of 308 nm, have been studied by means of time-resolved optical absorption spectroscopy, time-resolved resonance Raman scattering, and transient dielectric loss measurement. Only one of these triplet states exhibits resonance Raman scattering. It is concluded that this state is a TT* triplet state, in which the conjugation between the aldehyde and the naphthyl groups is broken and which does not have the character of a twisted intramolecular charge-transfer state.Bands in electronic absorption spectra of even relatively small molecules in liquid solutions are usually broad and with little or no vibrational structure. They are not so characteristic for the molecules as their IR and Raman spectra. Therefore IR spectra and Raman spectra may be more helpful than electronic absorption spectra in identifying intermediates in reactions unambiguously. Very often and in particular in the case of photochemical reactions the concentrations of reaction intermediates encountered in