A series of new coumarin containing compounds were synthesized from 4-bromomethylcoumarin derivatives and different heteroaromatic systems methylene thiolinker. Twenty-four compounds were screened biologically against two human tumor cell lines, breast carcinoma MCF-7 and hepatocellular carcinoma HePG-2, at the national cancer institute, Cairo, Egypt using 5-fluorouracil as standard drug. Compounds hh and showed strong activity against both MCF-7 and HepG-2 cell lines with being compound is the most active with IC values of 5.5 µg/ml and 6.9 µg/ml respectively. Docking was performed with protein 1KE9 to study the binding mode of the designed compounds.