indolizinoquinoline-5,12-dione derivatives (IQDs) are synthesized and evaluated for their cytotoxicactivities toward human lung adenocarcinoma (GLC-82), large-cell lung carcinoma (NCI-H460), promyelocytic leukemia (HL-60) and breast carcinoma (MCF-7) cells by MTT method. Most of the IQDs show significant cytotoxic potency. In addition, the evaluation of structure-activityrelationships indicated that the incorporation