Mononuclear nickel(II) thiolate complexes [(LNi)-Ni-tBu(SEt)] (1) and [(LNi)-Ni-tBu(aet)] (2, aet = S-(CH2)(2)NH2) (L-tBu = [HC(C(Bu-t)-NC6H3(Pr-i)(2))(2)](-)), supported by a bulky nacnac ligand, were synthesized by treatment of the nickel(II) bromide precursor [(LNi)-Ni-tBu(Br)] (I) with the potassium salts of ethanethiol and cysteamine, respectively. The nickel atom in 1 features a planar T-shaped environment, while the Ni ion within 2 shows a distorted square planar coordination geometry, as the aminoethanethiolate (aet) is coordinated as a chelating ligand. In 2 the beta-diketiminate ligand binds in a rarely observed kappa C-2,N coordination mode. Reduction of complex 1 or its benzenethiolate analogue [(LNi)-Ni-tBu(SPh)] (II) by KC8 resulted in the formation of dinuclear thiolates (K center dot OEt2)(K)[(LNi)-Ni-tBu(SEt)](2) (3) and (K center dot OEt2)(2)[(LNi)-Ni-tBu(SPh)](2) (4), respectively. In these compounds [(LNi)-Ni-tBu-(SR)](-) units are held together by potassium cations produced in the reduction process. All compounds mentioned were structurally characterized by singlecrystal X-ray crystallography.