The new ligand bis(2-picolyl)(2-hydroxy-3,5-di-tert-butylbenzyl)amine (HL) was prepared from bis(2-picolyl)amine and 2,4-di-tert-butyl-6-(chloromethyl)phenol. It acts as a tetradentate N,N,O tripod ligand ensuring 5-fold coordination in all its zinc complexes L . Zn-X. The central complex of the series was [L . Zn(OH2)]CIO4 (1) obtained from zinc perchlorate. Together with the more labile complex L . Zn-C2H5 (2), obtained from diethyl zinc, it was used as a starting material for ligand substitutions. In the presence of bases, 1 was converted to L . Zn-OH (3). [L . Zn(py)]ClO4 (4). and [(L . Zn)(3)(mu (3)-CO3)]ClO4 (5). Metathetical reactions produced the neutral complexes L Zn-X with X = Br (6), OAc (7), OC6H5 (8). SC6H5 (9). OP(O)(OPh)(2) (10), p-nitrophenolate (11). 1-methyluracilate (12). o-fhrmylphenolate (13), and o-hydroxymethylphenolate (14). Structure determinations of 1. 5. 7. 10. 11, 13, and 14 confirmed the strictly monodentate attachment of all units X in L Zn-X. The hydrolytic cleavage of tris(p-nitrophenyl) phosphate by 1 was investigated preparatively and kinetically. L Zn-OH was found to be the hydrolytically active nucleophile. The second-order rate constant for the cleavage reaction was Found to be slightly lower than the values for related systems, reflecting the steric hindrance in the tert-butyl-substituted ligand L.