Two enantiomers of a chiral binaphthyl-bridged salen dichlorozirconiurn (IV) complex (namely R-Lambda-1 and S-Delta-1) were synthesized and tested as pre-catalysts for 4-methyl-l-hexene (4MH) polymerization. Their behavior was compared with that of the same complex in its racemic form. Isotactic poly(4methyl-1-hexene) was produced in both case, but the polymerization of racemic 4MH promoted by the optically active catalysts preferentially consumed one antipode, showing some stereoselectivity for the process.