The isolation of the first family of thioether-coordinated nickel(III) complexes, [Ni(RxL)]PF6, incorporating acyclic ligands has been achieved using thioether-azo-oximes of the type HON=C(R)N=NC6H4S(CH2)(x)- SC6H4N=NC(R)=NOH (H2RxL, x = 2, 3; R = : Ph, a-naphthyl). The synthesis consists of electrooxidation of Ni-II(RxL) precursors having proven NiS2N4 coordination spheres. The [Ni(RxL)](+) species have a d(z)(2) ground state and display azo-N-14 superhyperfine EPR splitting. The nickel(III) state is stabilized well, the nickel(III)-nickel(II) reduction potential being relatively low.