The title compd. [RuL2(SCN)2].2H2O (L = 2,2'-bipyridine-4,4'-dicarboxylic acid), useful as photosensitizer for photovoltaic cells and photocatalyst, is prepd. by heating RuCl3.3H2O with 2,2'-bipyridine-4,4'-dicarboxylic acid at 110-150ツー in org. solvents in the dark followed by reaction of RuL2Cl2.2H2O with sodium thiocyanate. Thus, the title compd. was prepd. in 47% overall yield from RuCl3.3H2O. [on SciFinder(R)]