10.22376/ijpbs.2019.10.1.p1-12 Volume 2 Issue 3 2011 (July - September) Some 2,3-diaryl pyrazines and 5,6-diaryl-2,3-dihydropyrazine were synthesized and evaluated for their cytotoxicity study. 2,3-Diarylpyrazines were prepared from oxidation of 5,6-diarly-2,3-dihydropyrazine by sulfur. The synthesized compounds were tested for their cytotoxicity effects toward (MT-29) cancer cell line using MTT-assay. The results showed compounds 4a and 4b were two most active compounds. Parisa Miralinaghi, Mona Salimi, Sara Shirmohammadli And Mohsen Amini Diarylpyrazine, Diaryldihydropyrazine, Cytotoxicity, MT-29, 60-64