2-Vinyl- or heteroaryl-substituted anilines werereacted with diphosgene in acetonitrile solution via a reactive imidoyl moiety to afford the corresponding 2-chloroquinolines. Facile syntheses of nine 2-chloroquinoline derivatives from several anilines and their postulate mechanismis described. The postulate mechanism of 2-chloroquinolineformation via imidoyl moiety as a good leaving group showsthat the reaction consists of the following three steps: (1)generation of phenylisocyanate, (2) quinoline ring formation,and (3) chlorination on C2 position of quinoline.