Two diphenyl thioether-bridged binuclear metallocenes of Ti and Zr, [(C(5)H(5))Cl(2)MC(5)H(4)CH(2)(p-C(6)H(4))] (2)S [M = Ti (1) and Zr (2)], have been synthesized by treating the dilithium salts of the corresponding ligand [(C(5)H(5)CH(2)(p-C(6)H(4))](2)S with two equivalents of C(5)H(5)TiCl(3) and C(5)H(5)ZrCl(3)(DME), respectively, in toluene at 0 degrees C. Both new complexes have been characterized by (1)H-NMR spectroscopy and elemental analysis. Homogeneous ethylene polymerization using both complexes was performed in the presence of methylaluminoxane (MAO). The influences of molar ratio of [MAO]/[Cat], concentration of the catalysts, time, and temperature have been studied systematically. The catalytic activity of 1 is higher than that of the corresponding oxygen-bridged catalyst [(C(5)H(5))Cl(2)TiC(5)H(4)CH(2)(p-C(6)H(4))](2)O. The catalytic activity of 2 is at least two times higher than that of 1 under any tested polymerization conditions. The melting points of polyethylene (PE) produced by 1 and 2 are higher than 130 degrees C, indicating a highly linear and highly crystalline PE. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 120: 3530-3535, 2011