Fifteen benzothiazepine compounds were synthesized and their cytotoxicity was studied because of the significance of the benzothiazepine pharmacophore. Benzothiazepines were synthesised by combined 0.01 mol of 1,3-substituted prop-2-en-1-one, 0.01 mol of 2- aminothiophenol, 1.25 ml of water, and a pinch of zinc acetate as a catalyst in a conical flask. The solvent free reaction mixture was heated in a microwave oven for 2-3 minutes at a temperature of 80-85OC. Products were filtered, dried, and recrystallized in ethanol after being washed in water to remove the catalyst. The compounds' characterization was done using the IR, NMR and Mass spectroscopy. The in vivo cytotoxicity studies were performed using MTT assay method. Spectral data reveals the structure of the compound benzothiazepine. Of all the compounds tested against HT-29 cell lines, the compound BT-09 having a nitrophenyl moiety in its structure showed maximum activity with a IC50 value of 28 µg/mL. Among the compounds tested for cytotoxicity on MCF-7 cell lines, the compound BT-09 showed maximum activity (IC50 27 µg/mL). Among the compounds tested for cytotoxicity on DU-145 cell lines, the compounds, BT-09 and BT-11 showed maximum activity (IC50 16 µg/mL). It was also observed that most of the compounds tested on these three cell lines showed maximum activity on prostate cancer cell lines (DU-145). The cytotoxic results showed that the compound BT-09 with a nitrophenyl moiety in its structure was the most effective against the HT-29 cell line, MCF-7 cell line, and DU-145 cell line, with an IC50 value of 28 g/mL, 27 g/mL, and 16 g/mL, respectively.