As part of our search for anti-breast cancer agents a new series of tricyclic 4-substituted-2-yl)-2- thioxo-3, 4-dihydro-1H-indeno [1, 2-d] pyrimidin-5(2H)-one 4-9 were obtained in one pot synthesis by a modification of the Biginelli Reaction. The structures of the synthesized compounds were characterized by microanalyses, IR, 1H-NMR, 13C-NMR and mass spectral data. All the synthesized compounds were evaluated for their in vitro anticancer activity against human breast cancer cell line (MCF7). Most of the screened compounds showed interesting cytotoxic activities compared to Doxorubicin as reference drug. Compounds 8, 5, 7 and 4 (IC50 values 10.25, 23.48, 27.51 and 28.85 μM) revealed higher cytotoxic activities than the Doxorubicin as reference drug with IC50 value (32.00 μM). Also, compound 9 is nearly as active as Doxorubicin with IC50 values (33.55 μM). Compound 6 showed moderate activity.