The nuclearity of two preViously prepared nickel complexes, [LNiCl(µ-Cl)] 2 • 2CH 3 OH (1) and L′NiCl 2 (2) (L ) bis(1-methylbenzimidazoyl-2-methyl)amine and L′ ) bis(1-methylbenzimidazoyl-2-methyl)-10-camphorsulfonamide), was found to be temperature-dependent. Mononuclear [LNi(CH 3 OH) 2 Cl]Cl • 2H 2 O (3) and dinuclear [L′NiCl(µ-Cl)] 2 (4) were obtained as crystals at -20 °C. It is noteworthy that complex 2 can catalyze the conjugate addition of thiophenols to R,β-enones in high yields; in contrast, the same reaction catalyzed by NiCl 2 • THF or complex 3 was far less effectiVe.