In this study, some 1-methylene-2,,3-diaryl-1,2-dihydropyrazino[ 1,2-a]benzimidazole and some 1-(2-arylvinyl)-3-arylpyrazino[1,2-a]benzimidazole derivatives were synthesised. The structure elucidation of the compounds was performed by IR, H-1-NMR and MASS spectroscopic data and elemental analyses results. Anticancer and anti-HIV activities of the compounds were examined, however no anti-HIV activity was seen; highly notable anticancer activity was obtained. It was also observed that the compounds were more potent against leukaemia cell lines. (C) 2002 Published by Editions scientifiques et medicales Elsevier SAS.