Successful synthesis and characterization of the six-coordinated complex [Ru(STTP)(CO)Cl] (1; STTP = 5,10,15,20-tetratolyl-21-thiaporphyrinato) allowed the development of the coordination chemistry of ruthenium-thiaporphyrin through dechlorination and metathesis reactions. Accordingly, [Ru-II(STTP)(CO)X] (X = NO3- (2), NO2- (3), and N-3(-) (4)) was synthesized and analyzed by single-crystal X-ray structural determination and NMR, UV-vis, and FT-IR spectroscopic methods. An independent reaction of STPPH and [Ru(COD)Cl-2] led to [Ru-III(STTP)Cl-2] (5), which possessed a higher-valent Ru(III) center and exhibited good stability in the solution state. This stability allowed reversible redox processes in a cyclic voltammetric study. Reactions of [Ru(S2TTP)Cl-2] (S2TTP = 5,10,15,20-tetratolyl-21,23-dithiaporphyrinato) with AgNO3 and NaSePh, also via the metathesis strategy, resulted in novel dithiaporphyrin complexes [Ru-II(S2TTP)(NO3)(2)] (6) and [Ru-0(S2TTP)(PhSeCH2SePh)(2)] (7), respectively. The structures of 6 and 7 were corroborated by X-ray crystallographic analyses. Complex 7 is an unprecedented ruthenium(0)-dithiaporphyrin with two bis(phenylseleno)methanes as axial ligands. A comparison of the analyses of the crude products from reactions of NaSePh and CH2Cl2 with or without [Ru(S2TTP)Cl-2], further supported by UV-vis spectral changes under stoichiometric reactions between [Ru(S2TTP)Cl-2] and NaSePh, suggested a reaction sequence in the order of (1) formation of a putative [Ru-II(S2TTP)(SePh)(2)] intermediate, followed by (2) the concerted formation of PhSe-CH2Cl and simultaneously a reduction of Ru(II) to Ru(0) and finally (3) nucleophilic substitution of PhSeCH2Cl by excess PhSe-, resulting in PhSeCH2SePh, which readily coordinated to the Ru(0) and completed the formation of bis(phenylseleno)methane complex 7.