Electrochemical reductions of iron(II) 4,4′,4″,4′″-tetrasulfophthalocyanine (Fe(II)TSP) in dimethyl sulfoxide (DMSO) on a mercury electrode have been examined. The iron compound was found to undergo two one-electron reductions (at -0.74 and -1.15 V vs. SCE respectively) to Fe(0) as verified by polarographic measurements. The course of reduction was followed by observing the spectral change in a combined optical-electrochemical cell. The influence of such extraplanar ligands as cyanide, pyridine, and imidazole, etc., on the half-wave potentials were also noted.