Titanium and zirconium complexes with a pyridine diamide ligand, [2,6-(RNCH2)(2)NC5H3](2-) (PDMP; R = 2,6-dimethylphenyl) have been synthesized and their catalytic behaviors investigated for ethylene polymerization. It was found that the zirconium complexes, [PDMP]ZrCl2 (7) and [PDMP][ZrCl3 x THF](2) (8), gave higher activities than the titanium complexes, [PDMP]TiCl2 (5) and [PDMP][TiCl3](2) (6). The bimetallic complexes (6, 8) gave higher activities than the corresponding monometallic complexes (5, 7). The titanium complexes gave polymers with higher molecular weight (M-w) than the zirconium complexes. The molecular weight distribution (M-w/M-n) of the polymers obtained from the pyridine diamide complexes were much broader than that of the normal metallocene catalysts.