Three new highly substituted bis(2-picolyl)(2-hydroxybenzyl)amine ligands were synthesized, and their biomimetic zinc complex chemistry was explored. They have tert-butyl substituents at the 3-and 5-positions of their phenyl rings, and they bear one phenyl group (HL2), two methyl groups (Hl(3)), or two phenyl groups (HL4) at the 6-positions of their pyridyl rings. Their reactions with hydrated zinc perchlorate yield three distinctively different complex types. L-2 forms a trigonal-bipyramidal aqua complex, and L-3, a square-pyramidal aqua complex. The substituents on L-4 leave no room for a water ligand, and the resulting zinc complex is trigonal-monopyramidal with a vacant coordination site. The water ligands on the (LZn)-Zn-2 and (LZn)-Zn-3 units can be replaced by anionic halide, thiocyanate, p-nitrophenolate, benzoate, and organophosphate as well as uncharged pyridine ligands. The (LZn)-Zn-4 unit forms labile halide, p-nitrophenolate, and pyridine complexes. Triethylamine converts the aqua complexes to the labile hydroxides (LZn)-Zn-2-OH and (LZn)-Zn-3-OH, and in polar media [(LZn)-Zn-3-OH2](+) seems to be in equilibrium with (LZn)-Zn-3-OH. The hydroxides, but not the water complexes, effect the hydrolytic cleavage of tris(p-nitrophenyl) phosphate to bis(p-nitrophenyl) phosphate. The kinetic investigation of the cleavage reactions has shown them to be second-order reactions, thereby supporting the proposed four-center mechanism.