Improved high-yield synthesis of N-aryl azetidine-2,4-dione has been achieved. The azetidine-2,4-dione undergoes ring-opening reactions with aliphatic primary amines to form malonamide linkages. More importantly, this compound exhibits a high reactivity toward primary aliphatic arnine group over alcohols or secondary amines. This selective end-group functionalization is useful for preparing useful polymer intermediates. In this study polymalonamides were synthesized by fast addition reaction of aliphatic diamine and azetidine-2,4-dione. In the meantime, further application for structure-controlled reaction also has been demonstrated. (c) 2006 Wiley Periodicals, Inc.