A catalyst is disclosed for the polymerization and co-polymerization of olefins with functionalized monomers. The catalyst is formed from a combination of two neutral metal complexes, L(.sup.iPr.sub.2)M(CH.sub.2Ph)(PMe.sub.3)[L=N-(2,6-diisopropylphenyl)-2-(- 2,6-diisopropylphenylimino)propanamide] and M(COD).sub.2(COD=cyclooctadiene). The catalyst displays a unique mode of action and performs at ambient conditions producing high molecular weight polyolefins and co-polymers with functional groups. The polymerized olefins include ethylene, .alpha.-olefins and functionalized olefins.