Reduction of trans-[OsL2(O)(2)] (L- = [N(i-Pr2PS)(2)](-)) with hydrazine hydrate afforded a dinitrogen complex , possibly "[OsL2(N-2)(solv)]" (solv = H2O or THF), which reacted with RCN, R'NC, and SO2 to give trans-[OsL2(RCN)(2)] (R = Ph, 4-tolyl , 4-t-BuC6H4 ), trans-[OsL2(R'NC)(2)] (R' = 2,6-Me2C6H3 (xyl) , t-Bu , and [Os(L)(2)(SO2)(H2O)] complexes, respectively. Protonation of compounds , , and with HBF4 led to formation of dicationic trans-[Os(LH)(2)(N-2)(H2O)][BF4](2) , trans-[Os(LH)(2)(PhCN)(2)][BF4](2) , and trans-[Os(LH)(2)(xylNC)(2)][BF4](2) , respectively. Treatment of with phenylhydrazine and SnCl2 afforded trans-[OsL2(N2Ph)(2)] and trans-[OsL2Cl2] , respectively. Air oxidation of compound in hexane/MeOH gave the dimethoxy complex trans-[OsL2(OMe)(2)] , which in CH2Cl2 solution was readily air oxidized to. Compound is capable of catalyzing aerobic oxidation of PPh3, possibly via an Os(IV) intermediate. The formal potentials for the Os-L complexes have been determined by cyclic voltammetry. The solid-state structures of compounds cis-, and have been established by X-ray crystallography.