The compound [Ru 2 O(keto) 2 (py) 6 ](PF 6 ) 2 , keto = ketoprofen and py = pyridine, interacts with calf thymus-DNA with K b = 1.08 × 10 4 M À 1 . It efficiently quenches HSA fluorescence in different temperatures, with Ksv values in the 10 4 -10 5 M À 1 range, both by dynamic and static mechanisms. The data provided by the double logarithmic and van't Hoff approximations indicated a moderate (K b � 10 4 M À 1 ) and spontaneous (ΔG < 0) interaction, being enthalpically driven (ΔH = À 27.1 kJ mol À 1 and ΔS = À 5.3 J mol À 1 K À 1 ). Molecular docking calculations confirmed that the binuclear compound interacts with HSA more strongly than with DNA. The occurrence of a high contribution from electrostatic forces was observed, fully consistent with the bicationic nature of [Ru 2 O(keto) 2 (py) 6 ](PF 6 ) 2 . The molecular docking results also revealed that the interaction occurs in an external subdomain, explaining the lack of significant conformational changes in the protein, as probed by circular dichroism spectra.