Five multi-dentate ligands: N,N ''-di-(1,10-phenanthroline-2-methylene)-ethylenediamine (L1), N,N ''-di-(1,10-phenanthroline-2-methylene)-1,3-propanediamine(L2), 1,7-di-(1,10-phenanthroline-2-methylene)-1,4,7-triazaheptane (L3), 1,10-di-(1,10-phenanthroline-2-methylene)-1,4,7,10-tetraazatridecane (L4), 1,13-di-(1,10-phenanthroline-2-methylene)-1,4,7,10,13-pentaazatridecane (L5) have been synthesized and characterized. The hydrolytic kinetics catalyzed by dinuclear complexes of Zn(II) with L1-L5 have been studied in aqueous solution at 298.2 +/- 0.1 K, I = 0.10 mol dm(-3) KNO3 at physiological condition (pH 7.0-8.4), respectively. In this study it is found that the catalytic effect of Zn(2)L3 was the best one among the five dinuclear complexes for the hydrolysis of 2-hydroxy-propyl-p-nitrophenyl phosphate (HPNP). Its k(Zn2L2H.1), k(Zn2L2) and pK(a) are 0.0480 mol(-1) dm(3) s(-1), 0.000043 mol(-1) dm(3) s(-1) and 8.87, respectively. This paper expounds the result from the structure of the ligands and the properties of the metal ions, and deduces the catalysis mechanism. (C) 2008 Elsevier B.V. All rights reserved.