TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The metal atom is a cation of iron, cation of ruthenium (preferred), cation of osmium, cation of technetium and/or cation of rhodium. The acidic group is carboxylic acid group, sulfonic acid group, phosphonic acid group, sulfinic acid group and/or boronic acid group or their salts. The coordinative nitrogen atoms of the second ligand are present in aromatic radical. The semiconductor is titanium dioxide.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The composition further comprises third ligand of thiocyanate groups, isothiocyantes (both preferred), halogen atoms, hydroxyl groups, cyano groups, isocyanate groups, isocyanide groups, selenocyante groups or isoselenocyanate groups.Preferred Components: The second ligand is a biphenyl ligand of formula (II), preferably (2,2')bipyridinyl-4,4'-dicarboxylic acid.R7, R8 = halo, NO2, CN, carboxy group, OH, 1-20C aliphatic radical, 3-40C aromatic radical, or 3-40C cycloaliphatic radical; andc, d = 0-3. Preferred Definitions:    R3+R4 = imidazole compound of formula (III); and    R5, R6 = H, halo, NO2, CN, a carboxy group, OH, 1-20C aliphatic radical, 3-40C aromatic radical or 3-40C cycloaliphatic radical.    EXAMPLE - 1,10-Phenanthroline-5,6-dione (1.05 g), ammonium acetate (7.2 g), 4'-nonoxybenzaldehyde (6 mmol) and glacial acetic acid (60 ml) were refluxed for about 2 hours and cooled to room temperature and then neutralized with concentrated aqueous ammonia and the reaction mixture was worked up to give 2-(4'-nonoxy) phenylimidazo(4,5-f)1,10-phenanthroline. 2-(4'-Nonoxy)phenylimidazo(4,5-f)1,10-phenanthroline (1 equivalent) was dissolved in anhydrous dimethyl formamide and excess of sodium hydride was added. The reaction mixture was stirred at 100degreesC for further 30 minutes and then 1-bromoethane (2 equivalent) was added and stirred for 24 hours at 100degreesC. The reaction mixture was worked up to give 3-ethyl-2-(4'-nonoxy)phenylimidazo(4,5-f)1,10-phenanthroline. Ruthenium chloride-para-cymene complex ((RuCl2(p-cymene))2) (0.1 g) was dissolved in dimethyl formamide (40 ml) and 3-ethyl-2-(4'-nonoxy)phenylimidazo(4,5-f)1,10-phenanthroline (0.32 mmol) was added. The reaction mixture was heated to 80degreesC under argon for 5 hours with constant stirring. 2,2'-Bipyridine-4,4'-dicarboxylic acid (0.08 g) was then added to the reaction mixture and refluxed for 4 hours. Excess of ammonium thiocyanate (0.99 g) was added to the reaction mixture and refluxed for 4 hours and worked up to give cis-dithiocyanato-2,2'-bipyridyl-4,4'-dicarboxylate-3-ethyl-2-(4'-nonoxyphenyl)imidazo(4,5-f)1,0-phenanthroline ruthenium (II) complex (72%).