In the present work, the reaction of the acetoactanilide derivatives with either benzenediazonium chloride, 4‐chlorobenzenediazonium chloride, or 4‐methoxybenzenediazonium, gave arylhydrazone derivatives. Heterocyclizations of the latter compounds were carried out to afford new thiophene, pyran and pyridine derivatives. The cyctotoxicity of the synthesized compounds against the selected six cancer cell lines was determined where eleven compounds exhibited the highest inhibitions. Through out this work, the produced pyridazine derivatives were selected for evaluation against cancer cell lines categorized according to the disease and the compounds showed high inhibitions. The results obtained in this work encourage further work in the future.