A series of structurally new diheteroaryl thioether analogs was designed, prepared and screened toward MGC-803, MKN-45, EC-109 and H1650. Most of the target compounds displayed moderate to potent antiproliferative activities. Among them, compound 5 showed the best antiproliferative activity against the tested cell lines with the half maximal inhibitory concentration (IC50) values below 10μM. In addition, flow cytometry analysis showed that compound 5 increased Bax expression, down-regulated expression of Bcl-2, cleaved caspases-3/9, finally inducing apoptosis of MKN-45 cells as well asarrested the cell cycle at G2/M phase. This study suggests that the diheteroaryl thioethers are a class of emerging chemotypes for developing antitumor agents or biological probes, and compound 5 could serve as a good starting point to design new apoptosis inducers.