A novel ruthenium polypyridyl complex of [Ru(bpy)(2)(FcIP)] (PF6)(2)(bpy = 2, 2'-bipyridine, FcIP=2-ferrocenyl-imidazo[4,5-f]-1, 10-phenanthroline) was synthesized and characterized by elementary analysis and H-1 NMR. The binding of the complex to calf thymus(ct) DNA was investigated with absorption and luminescence spectroscopy titrations, steady-state emission quenching, and viscosity measurements. The results suggest that the complex acted as a ct-DNA intercalator with an intrinsic binding constant of (2.0 +/- 0.4) X 10(5) L/mol in buffered 50 mmol/L NaCl.