The 11-phenethyl-3,11-dihydro-2H-benzo[6,7]thiochromeno[2,3-d]thiazole-2,5,10-trione (3.6) displayed prominent cytotoxicity effects on leukemia (Jurkat, THP-1), epidermoid (KB3-1, KBC-1), colon (HCT116wt, HCT116 p53-/-), breast (MCF-7), and carcinoma cells. The gene discussed is TP53; the disease is carcinoma.