Three ruthenium complexes containing a bidentate piq ligand, [(piq)Ru(bpy)2]2+ (1), [(piq)Ru(phen)2]2+ (2), and [(piq)Ru(DIP)2]2+ (3) (piq = phenylisoquinolinate, bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline, DIP = 4,7-diphenyl-1,10-phenanthroline), were prepared. The DNA binding properties of complexes 1-3 to double-stranded DNA were studied. The binding of 1-3 to calf-thymus DNA (ct-DNA) yielded lower emission intensities than those observed with the corresponding Ru complexes alone. To explore potential interactions of complexes 1-3 with lipid-rich organs in live cells, the emission properties of the Ru probes were studied with liposomes. The emission intensities of complexes 1-3 were enhanced to similar extents upon interaction with liposomes. The cytotoxic activities of the complexes against MDA-MB-231 and HUVECs were evaluated in vitro. The effects of complexes 1-3 on the survival of MDA-MB-231 cells were examined and compared with that of cis-platin. Complexes 2 and 3 were more cytotoxic to cancer cells than cis-platin. Complexes 1-3 showed cellular uptakes of 1.1, 10.6, and 76.6%, respectively, indicating that the greatest amount of complex 3 entered the cancer cells. Inhibition of cell migration by complexes 1-3 was also evaluated by the wound healing assay.