Ring-opening polymerization of lactide by single-site catalysts is the most effective way to synthesize biodegradable polylactide. Unique tacticity and high activity can be tailored by ligand modification of the catalysts. In this work, chiral 5-coordinate aluminum catalysts bearing N,O bidentate ligands were synthesized from achiral Schiff base ligand. Their catalytic activities toward lactide polymerization are being investigated.