Asymmetric pinacol coupling of aromatic aldehydes with TiC14-Zn in the presence of enantiopure squaric acid amidoalcohols afforded 1,2-diols in excellent yields with high dl-diastereoselectivities and enantioselectivities in the range of 46-89% ee. Some factors influencing dl-diastereoselectivity and enantioselectivity were discussed. Asymmetric pinacol coupling of aromatic aldehydes with TiC14-Zn in the presence of enantiopure squaric acid amidoalcohols afforded 1,2-diols in excellent yields with high dl-diastereoselectivities and enantioselectivities in the range of 46-89% ee. Some factors influencing dl-diastereoselectivity and enantioselectivity were discussed.