Fluorescence excitation and dispersed emission spectra of tetrahydroisoquinoline are presented here. Two bands at 36 781 and 36 884 cm(-1) are confirmed from the spectral hole burning studies as two origins for two conformers. These bands correspond to the inequivalent twist conformers with the hydrogen atom attached to the nitrogen atom at axial and equatorial positions, respectively. The former is found to be the most stable one. SVL spectra are explained on the basis of two theoretically calculated low-frequency vibrations. These correspond to the butterfly and puckering motions of the benzene chromophore, respectively.