Binding of 3,5-di-tert-butyl-1,2-benzochatechol (H2DTBC) at Zn-II complexes of a tetradentate, tripodal ligand L is significantly enhanced (36-4.6 x 10(4) fold), and its reduction potential shifted (90-270 mV) to more positive values by introducing one to three amino hydrogen bond donors. The structure of one of the [(L)Zn(DTBC)] complexes is reported and shows intramolecular N-H center dot center dot center dot O hydrogen bonding between the ligand-based amino group and the Zn-II-bound chatecholate, which provides an explanation for the observed behavior.