Resonance Raman spectra of reduced porphycenes were measured in an effort to characterize structural changes concomitant with chemical reduction, Frequency shifts were observed for reduced porphycenes in certain skeletal vibrational modes. The observed resonance Raman behavior was generally consistent with the results of vibrational analysis by quantum chemical calculations based on density functional methods. (C) 2002 Published by Elsevier Science B.V.