The preparation and characterization of a mixed-valence pi-cation radical derivative of an iron(III) oxochlorinato complex is reported. The new complex has been synthesized by the one-electron oxidation of a pair of [Fe(oxoOEC)(Cl)] molecules to form the dimeric cation [Fe(oxoOEC)(Cl)](2)(+). The cation has been characterized by X-ray analysis, Mossbauer spectroscopy, UV-vis and near-IR spectroscopy, and magnetic susceptibility measurements from 6-300 K. The crystal structure shows that the two rings have a smaller overlap area than those of the formally related nickel and copper octaethylporphinate derivatives, reflecting the larger steric congestion at the periphery in part of the oxochlorin rings. The Mossbauer data is consistent with two equivalent iron(III) centers. The unpaired electron is delocalized over the two oxochlorin rings and mediates a strong antiferromagnetic interaction between the high-spin iron(III) centers.