Abstract: In this review the emphasis will be placed on the electrochemical rea-ctivity of synthetic metalloporphyrin complex in nonaqueous media. This review will summarize mechanistic data associated with the oxidation and reduction of metalloporphyrin and attempt to show the correlation of half-wave potentials (E_1/2) and electron transfer path ways with some factors such as substituent effect, axial-ligand coordination with nitrogeneous bases, with halide anions and with diatomic molecules; specific structure of the porphyrin ring system; basicity of the porphyrin ring; hydrogen ion-bonding with the solvent etc.