Trans-dihydroxo-[tetrakis(2,6-dichlorophenyl)porphinato]ruthenium(IV) ([Ru(OH) 2 (TDCPP)]) was prepared bymeta -chloroperbenzoic acid oxidation of [Ru(CO)(TDCPP)] in dichloromethane-toluene, and its crystal structure is reported. Crystal data for [Ru(OH) 2 (TDCPP)] 2toluene: C 4 4 H 2 2 N 4 O 2 Cl 8 Ru 2C 7 H 8 , orthorhombic, space group Pbca,a = 13.149(1), b = 19.893(2), c = 21.093(2) , U = 5517.3(2) 3 , Z = 4. The short axial Ru-O bond distance, 1.790(7) , is in the range expected for a double Ru(IV)-oxygen bond. Both hydroxo ligands are approximately located in the mean plane of two opposite dichlorophenyl groups. Full-matrix least-squares refinement of positional and thermal parameters, using 2368 unique reflections with F>2.5σ(F) led to R(F) = 0.063;R w = 0.066.