The methyl ester of N-allyl-2-methoxycarbonylsuccinanilic acid is partially converted to 1,1'-diallyl-4,4'-dihydroxy-1H,1'H-[3,3']biquinolinyl-2,2'-dione in refluxing toluene in the presence of metallic sodium. A possible mechanism for the occurrence of these chemical processes is discussed.