Lantern-type dinuclear complexes, cis-[Ru-2{3,5-(CF3)(2)-pf}(2)(O2CMe)(2)Cl] and [Ru-2{3,5-(CF3)(2)-pf}(3)(O-2 CMe)Cl] (3,5-(CF3)(2)-pf(-) = N,N'-bis[3,5-bis(trifluoromethyl)phenyl]formamidinate anion), were prepared and characterized. The cis-(2:2) and (3:1) arrangements of the formamidinate and acetate bridging ligands around the Ru-2(5+) core were confirmed by the X-ray crystal analysis as well as H-1 and F-19 NMR spectra (measured at 25 degrees C in CD2Cl2), where paramagnetic shifts were observed for the signals due to the unpaired electrons in the dinuclear core. Variable-temperature magnetic moments (2-300 K) showed the existence of three unpaired electrons in the dinuclear units with the large D values (60 cm(-1) for the cis-(2:2) Ru-2(5+) complex and 50 cm(-1) for the (3:1) Ru-2(5+) complex). The electronic state with S = 3/2 was also ascertained by the EPR spectra measured in solid at 4 K and in frozen toluene/ dichloromethane solution at 15 K, absorption spectra in dichloromethane and cyclic voltammograms (CVs) in THF using tetra-nbutyl ammonium perchlorate (TBAP) as electrolyte.