Aryl bromides of the type BrCeHz(CHzNMez)z-2,6-R-4 (R = NHz, MeO, H, C1, MeC(0)) have been synthesized and have been used to prepare the corresponding organonickel(I1) complexes [NitCsHz(CHzNMez)z-2,6-R-4)Brl by an oxidative addition reaction to Nio(COD)2 (COD = cycloocta-1,5-diene). The effect that the para substituent of the monoanionic, N,C,N' terdentate, aryl ligand has on the electronic properties of the nickel complexes has been investigated by 13C NMR and UV/vis spectroscopy as well as by electrochemistry. The results show that para substitution on the aryl ligand markedly influences the nickel(I1) center; electron-donating substituents increase the ease of oxidation to NiIII, and direct correlations exist between chemical shift data for the carbon atom bonded to nickel and appropriate Hammett parameters.