Two single oxygen-bridged heterobimetallic oxides of Al(III) with group 4 metals (Ti, Hf) have been prepared. The reaction of LAlMeOH (1) [L = CH(N(Ar)(CMe))(2), Ar = 2,6-iPr(2)C(6)H(3)] with dimethylmetallocenes of Ti and Hf in toluene (80 degrees C) and ether (room temperature), respectively, resulted in the formation of LAl(Me)(mu-O)M(Me)Cp-2 [M = Ti (2), Hf (3)] in moderate to good yield. Compounds 2 and 3 were characterized by elemental analysis, IR, NMR (H-1 and C-13), EI-MS, and single-crystal X-ray structural analysis. Furthermore, compound 2 showed good catalytic activity in ethylene and styrene homopolymerization, while compound 3 is less active in ethylene polymerization. The styrene polymerization yields atactic polystyrene.