Four Ru(11) DMSO complexes (M1R-M4R) having substituted flavones viz. 3-Hydroxy-2-(4-methoxyphenyl)-4H-chromen-4-one (HL1), 3-Hydroxy-2-(4-nitrophenyl)-4H-chromen-4-one (HL2), 3-Hydroxy-2-(4-dimethylaminophenyl)-4H-chromen-4-one (HL3) and 3-Hydroxy-2-(4-chlorophenyl)-4H-chromen-4-one (HL4) were synthesized and characterized by elemental analysis, IR, UV-Vis, H-1 NMR spectroscopies and ESI-MS. The molecular structures of the complexes were investigated by integrated spectroscopic and computational techniques (DFT). Both ligands as well as their complexes were screened for anticancer activities against breast cancer cell lines MCF-7. Cytotoxicity was assayed by MTT 13-(4, 5-dimethyl thiazol-2-yl)-2, 5-diphenyl tetrazonum bromide] assay. All ligands and their complexes exhibited significant cytotoxic potential of 5-40 mu M concentration at incubation period of 24 h. The cell cytotoxicity increased significantly in a concentration-dependent manner. In this series of compounds, HL2 (IC50 172 mu M) and its complex M2R (IC50 16 mu m) induced the highest cytotoxicity. (C) 2017 Elsevier B.V. All rights reserved,