As a continuation of our search for potential new anticancer agents, a series of ten flavonoid derivatives has been synthesized by cyclization of substituted chalcones. Target compounds were evaluated for their biological activity. Among them, compounds 1-4 and 9 displayed a significant growth inhibitory action against a panel of tumor cell lines including Jurkat, PC-3, and Colon 205. On treatment with an equitoxic (IC50) concentration, compounds 1-5 and 7-9 blocked cells in the G2/M phase of the Jurkat cell cycle, whereas compound 6 blocked the same in the G0/G1 phase. (c) 2005 Elsevier Ltd. All rights reserved.