Reaction of 1,3-bis(2′-Ar-imino)isoindolines (HL n , n=1–7, Ar=benzimidazolyl, N-methylbenzimidazolyl, thiazolyl, pyridyl, 3-methylpyridyl, 4-methylpyridyl, and benzthiazolyl, respectively) with Cu(OCH 3 ) 2 yields mononuclear hexacoordinate complexes with Cu(L n ) 2 composition. With cupric perchlorate square-pyramidal [Cu II (HL n )(NCCH 3 )(OClO 3 )]ClO 4 complexes (n=1, 3, 4) were isolated as perchlorate salts, whereas with chloride Cu II (HL n )Cl 2 (n=1, 4), or square-planar Cu II Cl 2 (HL n ) (n=2, 3, 7) complexes are formed. The X-ray crystal structures of Cu(L 3 ) 2 , Cu(L 5 ) 2 , [Cu II (HL 4 )(NCCH 3 )(OClO 3 )]ClO 4 , Cu II Cl(L 2 ) and Cu II Cl(L 7 ) are presented along with electrochemical and spectral (UV–Vis, FT-IR and X-band EPR) characterization for each compound. When combined with base, the isoindoline ligands in the [Cu II (HL n )(NCCH 3 )(OClO 3 )]ClO 4 complexes undergo deprotonation in solution that is reversible and induces UV–Vis spectral changes. Equilibrium constants for the dissociation are calculated. X-band EPR measurements in frozen solution show that the geometry of the complexes is similar to the corresponding X-ray crystallographic structures. The superoxide scavenging activity of the compounds determined from the McCord–Fridovich experiment show dependence on structural features and reduction potentials.