Dimeric (N2S)Ni complexes and the monomeric N2S2 bismercaptodiazacycloheptane nickel complex, (bme-dach)Ni, serve as precursors to two N2+, N'-/S-complexes where N-2=diazacycloheptane, N'=imidazole and S=thiolate. As rare examples of nickel complexes containing a mixed thiolate/imidazole ligand set, these complexes are characterized by X-ray diffraction, UV/vis, and variable temperature H-1 NMR spectroscopies, and electrochemistry. Density functional theory computations relate the orientation of the imidazole with respect to the N2N'SNi square plane to the VT NMR observed fluxionality and activation parameters. The superoxide dismutase activity of the imidazole complexes was investigated by the nitroblue tetrazolium assay.