Several N-(heterocyclic)-1H-isoindole, were prepared from hydrazine carboxylic acid-1,3-dioxo-1,3-dihydro-isoindole-2-yl ester for the purpose of possible genotoxic activity against cancer cell line of mouse spleen.In conclusion, the correlation between chromosomal aberrations induction, suppression of proliferation rate and antitumour activity observed in this study, appeared to further substantiate the validity of the chromosomal aberration assay as a possible method for improving and guiding chemotherapy.