Treatment of 2-(methylsulfinyl)benzaldehyde (1) with ethylenediamine or (1R,2R)-(-)-1,2-diaminocyclohexane afforded N,N'-bis[2-(methylsulfinyl)benzylidene]ethylenediamine (L-1) or (1R,2R)-N,N'-bis[2-(methylsulfinyl)benzylidene]-1,2-cyclohexanedia mine (L-2), respectively. Lithiation of 2-bromobenzaldehyde diethylacetal with n-BuLi/TMEDA followed by reaction with (1R,2S,5R)-(-)-menthyl-(S)-p-toluenesulfinate afforded 2-(S)-(p-tolylsulfinyl)benzaldehyde diethyl acetal (2). Deprotection of 2 with pyridinium tosylate followed by condensation with ethylenediamine, (1R,2R)-(-)-diaminocyclohexane, or (S,S)-(+)-diaminocyclohexane afforded N,N'-bis[2-(S)-(p-tolylsulfinyl)benzylidene]ethylenediamine (L-3), (1R,2R)-N,N'-bis[2-(S)-(p-tolylsulfinyl)benzylidene]-1,2-cyclohexanediamine ((R,R)-L-4), or (S,S)-N,N'-bis[2-(S)-(p-tolylsulfinyl)benzylidene]-1,2-cyclohexanediamine ((S,S)-L-4), respectively. Treatment of [Ru(PPh3)(3)Cl-2] with L afforded trans-[Ru(L)Cl-2] [L = L-1 (3), L-2 (4), L-3 (5), (R,R)-L-4 ((R,R)-6), (S,S)-L-4 ((S,S)-6)]. The X-ray structures of (S-S,R-S)-4, (R,R)-6, and (S,S)-6 have been determined. The average Ru-N, Ru-S, and Ru-Cl distances in (S-S,R-S)-4 are 2.063, 2.2301, and 2.4039 Angstrom, respectively. The corresponding distances in (R,R)-6 are 2.071, 2.256, and 2.411 Angstrom, and those in (S,S)-6, 2.058, 2.2275, and 2.3831 Angstrom. Compound 3 exhibited a reversible Ru(III/II) couple at 0.56 V vs CP2Fe+/0 in CH2Cl2. Treatment of 3 with AgNO3 in water afforded the aqua compound trans-[Ru(L-1)Cl(H2O)][PF6] (7), which has been characterized by X-ray crystallography. The Ru-Cl, Ru-O, average Ru-N, and average Ru-S distances in 7 are 2.3733(6), 2.1469(16), 2.071, and 2.2442 Angstrom, respectively. Treatment of 3 with AgNO3 followed by reaction with PPh3 afforded [Ru(L-1)(PPh3)(2)][PF6](2) (8). Treatment of [Os(PPh3)(3)Cl-2] with L-1 resulted in deoxygenation of one sulfoxide group of L-1 and formation of [Os(L-5)Cl-2(PPh3)] (9) (L-5 = N-[2-(methylsulfinyl)benzylidene]-N'-[2-(methylthio)benzylididene]ethylenediamine), which has been characterized by X-ray crystallography. The average Os-S(O), Os-N(trans to P), Os-N(trans to S), Os-P, and Os-Cl distances are 2.1931, 2.085, 2.175, 2.3641, and 2.4266 Angstrom, respectively.