Hole-burning spectra of 2H-benzotriazole and 2D-benzotriazole have been recorded in a range 1250 cm(-1) above the electronic origin to rule out the possibility that the other tautomer (1H-benzotriazole) absorbs in this frequency range. After establishing the existence of only one absorbing species by spectral hole-burning spectroscopy, dispersed fluorescence spectra taken through several low-frequency vibronic bands of 2H(2D)-benzotriazole have been recorded. The ground-stale vibrational frequencies are compared to results of an ab initio MP2 based normal-mode analysis. Assignments of S-1 vibrations to specific ground-state vibrations were established using the propensity rule. The rotational band contours of the vibronic 2H- and 2D-benzotriazole transitions have been determined to be pure a- or b-type. This can be traced back to the existence of two close lying electronically excited states of 2H-benzotriazole.