Abstract 4-Chloro-2-oxo-1, 2-dihydroquinoline-3-carboxylic acids and their esters react with aminopyridines in refluxing DMF to give the corresponding 4-hydroxy-2-oxo-1, 2- dihydroquinoline-3-carboxylic acid pyridylamides. Their structures were proved by 1 H NMR and mass spectroscopy, counter synthesis, and by X-ray analysis. A possible mechanism is proposed for the indicated chemical reaction.