The electron transfer reactivities of dirhenium and dirhodium carbonyl complexes of the macrocyclic ligands 5,7,12,14-tetramethyldibenzo [b,i] [1,4,8,11] tetraaza [14] annulene, (TMTAA), dibenzo [b,i] [1,4,8,11] tetraaza [14] annulene, (TAA), and tetraphenylporphyrin, (TPP) were investigated by cyclic voltammetry and differential pulse polarography. Potentials are reported for the electrochemical generation of π cation and π anion radicals of these complexes in the solvents dichloromethane and dimethylformamide. The potential differences between the π radical reactions of the metallomacrocyclic complexes were compared to the potential differences of the π radical reactions of the free macrocycles.