[Cu(II)(4,4'-dimethyl-2,2'-bipyridine)(3)](PF6)(2) (2) and [Cu(II) (5,5'-dimethyl-2,2'-bipyridine)(3)](PF6)(2) (4) were used together with aluminium isopropoxide and (1-bromoethyl)benzene in the controlled radical polymerization of styrene resulting in polystyrenes with predetermined molecular weight and narrow molecular weight distribution. The received polymers are colorless with a content of copper lower than 210 ppm. The substitution pattern at the bipyridine ligands has a distinct influence on the polymerization. The rate of polymerization of styrene using 2/[(CH3)(2)CHO](3)Al/C6H5CH(CH3)Br is two times larger than utilizing 4/[(CH3)(2)CHO](3)Al/C6H5CH(CH3)Br.