Novel titaniumcomplexes containing monoanionic [NOP] ligands based on a phenoxy−imine ligand and their derivatives were synthesized and characterized. Their performance as ethylene polymerization and copolymerization catalysts were studied. Upon treatment with MMAO, the [NOP]TiCl3 complexes were robust and highly active for the polymerization of ethylene, even at very low cocatalyst/catalyst ratios