Splitting of the oxygen-bridged dimer {In(III)(OEPO)}(2) [where (OEPO)(3-) is the trianion of octaethyloxophlorin] by potential axial ligands has been examined and compared to results obtained previously for the cleavage of {Fe(III)(OEPO)}(2). Treatment of {In(III)(OEPO)}(2) with an excess of imidazole (im) produced the crystalline complex {(im)(2)In(III)(OEPO...im)}(2).(im)(2)In(III)(OEPO).2Cl(2)C(6)H(4). This solid contains two different (im)(2)In(III)(OEPO) units that are bridged through hydrogen bonding by an uncoordinated imidazole. Treatment of {In(III)(OEPO)}(2) with an excess of pyridine (py) produced (py)(2)In(III)(OEPO), which is isostructural with (py)(2)Fe(III)(OEPO). Although {Fe(III)(OEPO)}(2) reacted with xylyl isocyanide (xylylNC) to form the novel free-radical complex (2,6-xylylNC)(2)Fe(II)(OEPO(*)) [where (OEPO(*))(2-) is the radical dianion of octaethyloxophlorin], {In(III)(OEPO)}(2) was unreactive toward xylyl isocyanide.