Compounds that combine metal-based drugs with covalently linked targeted organic agents have been shown, in some instances, to exhibit superior anticancer properties compared to the individual counterparts. Within this framework, we prepared a series of organometallic ruthenium(II)- and osmium(II)-p-cymene complexes modified with the nonsteroidal anti-inflammatory drugs (NSAIDs) indomethacin and diclofenac. The NSAIDs are attached to the organometallic moieties via monodentate (pyridine/phosphine) or bidentate (bipyridine) ligands, affording piano-stool Ru(II) and Os(II) arene complexes of general formula [M(eta(6)-p-cymene)Cl-2(N)], where N is a pyridine-based ligand, {2-(2-(1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indo1-3-yl) acetoxy) ethyl-3-(pyridin-3-yl)propanoate} or {2-(2-(24(2,6-dichlorophenyl)amino)-phenyl)acetoxy)ethyl-3-(pyridin-3-71)propanoate}, [M(eta(6)-p-cymene)Cl-2(P)], where P is a phosphine ligand, {2-(2-(1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indol-3-yOacetoxy)ethyl-(diphenylpho sphanyl) benzo ate} or {2- (2- (2-((2,6-dichlorophenyl) amino)phenyl) acetoxy) ethyl-4-(diphenylphosphanyl)-benzoate, and [M(eta(6)-p-cymene)Cl(N,N')][Cl], where N,N' is a bipyridine-based ligand, (4'-methyl-[2,2'-bipyridin]-4-yOmethyl-2-(1-(4-chlorob enzoyl)-5-methoxy-2-methyl-1H-in dol-3-yl) acetate), (4'-methyl- [2,2'-bipyridin]-4-yl) methyl-2-(2-((2,6-dichlorophenyl) amino)phenyl) acetate), (bis (2- (2- (1- (4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indo1-3-71)acetoxy)-ethyl)[2,2'-bipyridine]-5,5'-dicarboxylate), or (bis(2-(2-(24(2,6-dichlorophenyl)amino)phenyl)acetoxy)ethyl)[2,2'-bipyridine]-5,5'-dicarboxylate). The antiproliferative properties of the complexes were assessed in human ovarian cancer cells (A2780 and A2780cisR, the latter being resistant to cisplatin) and nontumorigenic human embryonic kidney (HEK-293) cells. Some of the complexes are considerably more cytotoxic than the original drugs and also display significant cancer cell selectivity.