As part of our efforts to develop the transition metal chemistry of corrolazines, which are ring-contracted porphyrinoid species most closely related to corroles, the vanadium and copper complexes (TBP)(8)Cz(H)O-IV (1) and (TBP)(8)CzCu(III) (2) of the ligand octakis(para-tert-butylphenyl)corrolazine [(TBP)(8)Cz] have been synthesized. The coordination behavior, preferred oxidation states, and general redox properties of metallocorrolazines are of particular interest. The corrolazine ligand in 1 was shown to contain a labile proton by acid/base titration and IR spectroscopy, serving as a -2 ligand rather than as the usual -3 donor. The oxidation state of the vanadium center in 1 was shown to be +4, in agreement with the overall neutral charge for this complex. The EPR spectrum of 1 reveals a rich signal consistent with a V-IV(O) (d(1), S = 1/2) porphyrinoid species (g(xx) = 1.989, g(yy) = 1.972, g(zz) = 1.962). The electrochemical analysis of 1 shows behavior closer to that of a porphyrazine than a corrolazine, with a positively shifted, irreversible reduction at -0.65 V (vs Ag/AgCl). Resonance Raman and IR data for 1 confirm the presence of a triply bonded terminal oxo ligand with v((VO)-O-16) = 975 cm(-1) and v((VO)-O-18) = 939 cm(-1). The copper complex 2 exhibits a diamagnetic H-1 NMR spectrum, indicative of a bona fide square planar copper(III) (d(8) low-spin) complex, Previously reported copper corroles have been characterized as copper(III) complexes which exhibit a paramagnetic NMR spectrum at higher temperatures, indicative of a thermally accessible triplet excited state ([(corrole(.+))Cu-II]). The NMR spectrum for 2 shows no paramagnetic behavior in the range 300-400 K, indicating that compound 2 does not have a thermally accessible triplet excited state. These data show that the corrolazine system is better able to stabilize the high oxidation state copper center than the corresponding corroles. Electrochemical studies of 2 reveal two reversible processes at +0,93 and -0.05 V, and bulk reduction of 2 with NaBH4 generates the copper(II) species [(TBP)(8)CzCu(II)](2a), which exhibits an EPR signal typical of a copper(II) porphyrinoid species.