Novel indolylpyrimidines and indolylpyrazines have been synthesized as potential antitumor agents. They were screened in a panel of 60 human tumor cell lines in vitro. Compounds 7, 9, 10, 15, 21 exhibited efficiently cytotoxic activities with GI50 values in the low micromolar range against a variety of human cancer cell lines. 2, 4-Bis (3′-indolyl) pyrimidine 8 displayed selective cytotoxic activity against IGROV1 tumor cell line with the GI50 value ...