Heterobimetallic nitrido porphyrin complexes with the [(L)(por)M-N-M'(L-OEt)Cl-2] formula {por(2-) = 5,10,15,20-tetraphenylporphyrin (TPP2-) or 5,10,15,20-tetra(p-tolyl)porphyrin (TTP2-) dianion; L-OEt(-) = [Co(eta 5-C5H5){P(O)-(OEt)(2)}(3)](-); M = Fe, Ru, or Os; M' = Ru or Os; L = H2O or pyridine} have been synthesized, and their electrochemistry has been studied. Treatment of trans-[Fe(TPP)(py)(2)] (py = pyridine) with Ru(VI) nitride [Ru(L-OEt)(N)Cl-2] (1) afforded Fe/Ru mu-nitrido complex [(py)(TPP)Fe(mu-N)Ru(L-OEt)Cl-2] (2). Similarly, Fe/Os analogue [(py)(TPP)Fe(mu-N)Os(L-OEt)Cl-2] (3) was obtained from trans-[Fe(TPP)(py)(2)] and [Os(L-OEt)(N)Cl-2]. However, no reaction was found between trans-[Fe(TPP)(py)(2)] and [Re(L-OEt)(N)Cl(PPh3)]. Treatment of trans-[M(TPP)(CO)(EtOH)] with 1 afforded mu-nitrido complexes [(H2O)(TPP)M(mu-N)Ru(L-OEt)Cl-2] [M = Ru (4a) or Os (5)]. TTP analogue [(H2O)(TTP)Ru(mu-N)Ru(L-OEt)Cl-2] (4b) was prepared similarly from trans-[Ru(TTP)(CO)(EtOH)] and 1. Reaction of [(H2O)(por)M(mu-N)M(L-OEt)Cl-2] with pyridine gave adducts [(py)(por)M(mu-N)Ru(L-OEt)Cl-2] [por = TTP, and M = Ru (6); por = TPP, and M = Os (7)]. The diamagnetism and short (por)M-N(nitride) distances in 2 [Fe-N, 1.683(3) ] and 4b [Ru-N, 1.743(3) ] are indicative of the (MN)-N-IV == M'(IV) bonding description. The cyclic voltammograms of the Fe/Ru (2) and Ru/Ru (4b) complexes in CH2Cl2 displayed oxidation couples at approximately +0.29 and +0.35 V versus Fc(+/0) (Fc = ferrocene) that are tentatively ascribed to the oxidation of the {LOEtRu} and {Ru(TTP)} moieties, respectively, whereas the Fe/Os (3) and Os/Ru (5) complexes exhibited Os-centered oxidation at approximately -0.06 and +0.05 V versus Fc(+/0), respectively. The crystal structures of 2 and 4b have been determined.