Cyclization of benzene-1,4-dicarbaldehyde dioxime 1 with different aromatic aldehydes in inert atmosphere yielded the corresponding new bisdioxazoles 2-11. The structure of 2-11 was elucidated by spectral data. In vitro antiamoebic activity was performed against HM1:IMSS strain of Entamoeba histolytica. The results showed that the compounds 3 (IC(50)=1.22 microM), 4 (IC(50)=1.41 microM), 7 (IC(50)=1.05 microM) and 10 (IC(50)=1.01 microM) exhibited better antiamoebic activity than the standard drug metronidazole (IC(50)=1.80 microM). The compounds 3, 4, 7 and 10 were tested for toxicity by MTT assay on H9c2 cardiac myoblasts and the results showed that the compounds 3, 4, 7 and 10 offered remarkable viability of 96.2%, 83.5%, 82% and 89%, respectively at a concentration of 12.5 microg/ml.