Symmetrical diaryl ${alpha}-diketones$ were synthesized in moderately good yields through the palladium catalyzed reaction of aryl iodides with carbon monoxide. The reaction was tolerant of a wide variety of fuctionalities($OCH_3,;CH_3,;NO_2,;OH,;COOH$) on the aryl iodide. On the other hand, the similar reaction of aryl bromides or chlorides with carbon monoxide did not proceed.