The unprecedented nickel(III) thiolate (Ni-III(OR)(P(C6H3-3-SiMe3-2-S)(3))](-) [R = Ph (1), Me (3)] containing the terminal Ni-III-OR bond, characterized by UV-vis, electron paramagnetic resonance, cyclic voltammetry, and single-crystal X-ray diffraction, were isolated from the reaction of [Ni-III(Cl)(P(C6H3-3-SiMe3-2-S)(3))](-) with 3 equiv of [Na][OPh] in tetrahydrofuran (THF)-CH3CN and the reaction of complex 1 with 1 equiv of [Bu4N][OMe] in THF-CH3OH, respectively. Interestingly, the addition of complex 1 into the THF-CH3OH solution of [Me4N][OH] also yielded complex 3. In contrast to the inertness of complex (Ni-III(Cl)(P(C6H3-3-SiMe3-2-S)(3))](-) toward 1 equiv of (Na][OPh], the addition of 1 equiv of [Na][OMe] into a THF-CH3CN solution of [Ni-III(Cl)(P(C6H3-3-SiMe3-2-S)(3))](-) yielded the known [Ni-III(CH2CN)(P(C6H3-3-SiMe3-2-S)(3))](-) (4). At 77 K, complexes 1 and 3 exhibit a rhombic signal with g values of 2.31, 2.09, and 2.00 and of 2.28, 2.04, and 2.00, respectively, the characteristic g values of the known trigonal-bipyramidal Ni-III [Ni-III(L)(P(C6H3-3-SiMe3-2-S)(3))](-) (L = SePh, SEt, CI) complexes. Compared to complexes [Ni-III(EPh)(P(C6H3-3-SiMe3-2-S)(3))](-) [E = S (2), Se] dominated by one intense absorption band at 592 and 590 nm, respectively, the electronic spectrum of complex 1 coordinated by the less electron-donating phenoxide ligand displays a red shift to 603 nm. In a comparison of the Ni-III-OMe bond length of 1.885(2) A found in complex 3, the longer Ni-III-OPh bond distance of 1.910(3) A found in complex 1 may be attributed to the absence of a and - donation from the [OPh]-coordinated ligand to the Ni-III center.