Resonance Raman (RR) spectra are reported for vanadyl octaethylporphyrin, OV(OEP), tetramesityltetramethylporphyrin, OV(TMTMP), and tetramesitylporphyrin, OV(TMP), and their corresponding pi-cation radicals obtained by chemical and electrochemical oxidation. The behavior of the nu(2) RR porphyrin "marker band", which moves to higher frequency upon oxidation of the OV(OEP) and OV(TMTMP) and to lower frequency for OV(TMP), shows that the resultant cation radicals have predominantly (2)A(1u) and (2)A(2u) ground states, respectively. In contrast to earlier work (Macor, K. A.; Czernuszewicz, R. S.; Spiro, T. G. Inorg. Chem. 1990, 29, 1996), it is demonstrated here that the shift of the nu(V=O) is insensitive to radical type, behavior which is in agreement with similar studies of the ferryl analogues (Czarnecki, K.; et al. J. Am. Chem. Soc. 1996, 116, 2929 and 4680). It is suggested that the observed downshifts of the nu(V=O) previously reported for RR spectra of vanadyl porphyrin pi-cation radicals, relative to their neutral parents, are most reasonably ascribed to trans oxo ligand coordination (most probably a water molecule) during low-temperature electrochemical oxidation of the neutral species.