A series of substituted 2-phenyl-4- quinolones, 2-phenyl naphthyridin-4-ones and their prodrugs were synthesized and evaluated for their anti-cancer activities. Among them, CHM-2133P was the most promising agent. To investigate the in vivo anti-tumor activity of CHM-2133P, we carried out xenografts with MCF-7 cells in athymic SCID mice. CHM-2133P induced a dose-dependent inhibition of tumor growth. The body weights of treated animals were not significantly affected by CHM-2133P. In this study we identified that CHM- 2133P, as a potential novel anti-mitotic agent, which possess potent and selective anti-tumor activity against MCF-7 in vitro and in vivo tests.