The electrochemical and spectroelectrochemical properties of [(TpTP)M(V)(L)(2)]Cl-+(-) in dichloromethane are presented where M = P or Sb, L = OCH3- or Cl-, and TpTP is the dianion of tetra-p-tolylporphyrin. All four porphyrins undergo two one-electron reductions on the cyclic voltammetry time scale to give initially porphyrin rr anion radicals and dianions. The singly and doubly reduced products of [(TpTP)MV(OCH3)(2)]Cl-+(-) are relatively stable, but this is not the case for the two [(TpTP)M(V)Cl(2)]Cl-+(-) complexes, both of which undergo a series of chemical reactions following electron transfer. The coupled electrochemical/chemical reactions lead to a low-valent M(III) complex in the case of the bis(chloro) Sb(V) derivative and to numerous decomposition products, including the free base porphyrin, in the case of the bis(chloro) P(V) porphyrin. UV-visible spectroelectrochemical and EPR data suggest that the four investigated porphyrins all undergo an internal charge transfer from the electrogenerated porphyrine anion radical to the Sb(V) or P(V) porphyrin center. The EPR spectrum of singly reduced [(TpTP)(SbCl2)-Cl-V]Cl-+(-) at 123 K in CH2Cl2 has a signal centered at g = 2.018 and exhibits hyperfine splitting due to interaction between the metal and the unpaired electron on the porphyrin macrocycle. The three other singly reduced porphyrins display a specturm with broad isotropic signals centered at g similar to 2.00 and a spectral line width which increases with temperature, also supporting an internal charge transfer mechanism.