A novel and efficient three-component one-pot synthesis of benzo[?]1,8-naphthyridines by 2-amino-4-methylquinoline, aromatic aldehydes, and malononitrile was done. The reaction was catalyzed by an acidic Bismuth(III) chloride, functionalized Bismuth(III) chloride, at room temperature to give various benzo[?]1,8-naphthyridines in high yields. The Bismuth(III) chloride is an environmentally friendly catalyst.