2-Methyl-1-substituted-imidazo [4, 5-g] quinoline-4, 9-diones and 7, 8-dihydro-10H-[1, 4] oxazino-[3′, 4′: 2, 3] imidazo [4, 5-g] quinoline-5, 12-dione (19) derivatives have been synthesized from 6, 7-dichloro-5, 8-quinolinedione for developing the new anticancer drugs. Our study on the cytotoxicity of imidazoquinolinedione derivatives has revealed that 7, 8- dihydro-10H-[1, 4] oxazino-[3′, 4′: 2, 3] imidazo [4, 5-g] quinoline-5, 12-dione (19), a ...