The ligand (N1‐[3‐(2‐aminoethylimino)‐1,1‐dimethylbutyl]ethane‐1,2‐diamine), L1, induces a high ligand field on the central NiII ion. Thus it is relatively easy to oxidize(NiIIL1)2+. However, the kinetic stability of the NiIIIL1 complexes is considerably lower than that of their analogous macrocyclic complexes. This difference in stabilities isattributed to the less rigid ligand framework, which facilitates the oxidation of ligand. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)