Further investigation of the flavonoid constituents of Pongamia pinnata from Japan resulted in the isolation of 18 flavonoid compounds including nine new ones, ponganones III-XI, from its root bark. The new structures were determined to be (2S)-3',4'-dimethoxy-6",6"-dimethylpyrano[2",3":7,8]-flavanone (III), (23)-6,3',4' trimethoxy-6",6"-dimethylpyrano[2",3": 7,8]-flavanone (IV), (2S)-7-methoxy-6-O-y,y~dimethylallyl-3',4'-methylenedioxyflavanone (V), 2'-hydroxy-3,4,5'-trimethoxy-6"\$"-dimethylpyrano [2",3" :4',3']chalcone (VI), 2',4'-dimethoxy-3,4-methylenedioxydioxydihydrochalcone (VII), 2',5',8-trimethoxy-3,4-methylenedioxy-6'methylpyrano [2",3" : 4',3']dihydrochalcone (VIII), 2&dimethoxy-3,4-methylenedioxy-furano [2",3" : 4',3']-dihydrochalcone (IX), 8-hydroxy-2',4',6'-trimethoxy-3,4-methylenedioxyc~lcone (X) and 3-methoxy-furano-[2",3":7,6]flavone (XI), respectively, by means of spectral analysis and synthesis.