Several mono- and bimetallic complexes of Fe(II) and V(III) with binucleating macrocyclic systems have been prepared. Electrochemical studies of complexes containing Fe(II) in the 6-coordinate site have shown that the FE(II/III) potential is affected by the length of the diamine chelate in this sin and by the occupancy of the open site. Oxidation of the Fe-II-V-III complex, A, with 2,4,6-trimethyliodosobenzene produced the Fe-II-V-III complex, B. Both A and B have been characterized by X-ray crystallography, cyclic voltammetry, and infrared and electronic spectroscopy. The origins of deactivation of two-metal oxidation in bimetallic complexes an discussed primarily in terms of the ligand reorganizational energy, which is caned mechanical coupling.