TECHNOLOGY FOCUS - ELECTRONICS - Preferred Composition: The photoelectric conversion element has an electrolyte layer and counter electrode.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The semiconductor fine particles are chosen from titanium oxide particles, zinc oxide particles and thin oxide particles.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (disclaimed): Mononuclear ruthenium complex of formula (V) and mononuclear ruthenium complex of formula (VI), are reacted, to obtain intermediate compound of formula (VII) which is then hydrolyzed, to obtain binuclear ruthenium complex dye (I). Preferred Component: The binuclear ruthenium complex dye is preferably of formula (II), (III) or (IV). Preferred Definitions:    R=carboxy;    n=0;and    Ar'=formula (d).    SPECIFIC COMPOUNDS - 8 Binuclear ruthenium complex dyes e.g. -(5-hexylthiophen-2-yl)thiophen-2-yl)-20',20'-bis(1-pyridin-1-yl)-4'',12''-dinonyl-7'',7''',8',9'',9''',10'-dispiro(fluorene-9,9'-(1,8,10,17)tetraaza-(20)ruthenahexacyclo(15.2.1.02,7.08,19.010,18.011,16)icosane-9',8''-(7,9)diaza-(8)ruthenatricyclo(7.4.0.02,7)tridecane-20',8'''-(7)aza-(9)azatricyclo(7.4.0.02,7)tridecan)-1''(9''),1'''(9'''),2',2''(7''),2''',3'',4',4''',5'',6',6''',8'(19'),10'(18'),10'',10''',11'(16'),12',12'',12''',14'-icosaene-4''',12'''-dicarboxylate-hexafluoro-phosphanuide of formula (Ia), 4''-(5-(5-hexylthiophen-2-yl)thiophen-2-yl)-1',7'',7''',7'''',9'',9''',9'''',17'-dispiro(fluorene-9,20'-(1,8,10,17)tetraaza-(9)ruthenahexacyclo(15.2.1.02,7.08,19.010,18.011,16)icosane-9',8''-(7,9)diaza-(8)ruthenatricyclo(7.4.0.02,7)tridecane-9',8'''-(7)aza-(9)aza-(8)ruthenatricyclo(7.4.0.02,7)tridecane-20',8''''-(7)aza-(9)azatricyclo(7.4.0.02,7)tridecane)-1'(19'),1''(9''),1'''(9'''),1''''(9''''),2',2''(7''),2''',2'''',3'',4',4''',4'''',5'',6',6''',6'''',10'',10''',10'''',11'(16'),12',12'',12''',12'''',14',17'-hexacosaene-3,4'''',6,12''''-metane tetracarboxylate, 4'',4''',12'',12'''-tetrakis((E)-2-(4-methoxyphenyl)ethenyl)-1',7'',7''',7'''',9'',9''',9'''',17'-dispiro(fluorene-9,20'-(1,8,10,17)tetraaza-(9)ruthenahexacyclo(15.2.1.02,7.08,19.010,18.011,16)icosane-9',8''-(7,9)diaza-(8)ruthenatricyclo(7.4.0.02,7)tridecane-9',8'''-(7)aza-(9)aza-(8)ruthenatricyclo(7.4.0.02,7)tridecane-20',8''''-(7)aza-(9)azatricyclo(7.4.0.02,7)tridecane)-1'(19'),1''(9''),1'''(9'''),1''''(9''''),2',2''(7''),2''',2'''',3'',4',4''',4'''',5'',6',6''',6'''',10'',10''',10'''',11'(16'),12',12'',12''',12'''',14',17'-hexacosaene-3,4'''',6,12''''-tetracarboxylate, 6-(hexyloxy)-3-((E)-2-(4-(hexyloxy)phenyl)ethenyl)-1',7'',7''',7'''',9'',9''',9'''',17'-dispiro(fluorene-9,20'-(1,8,10,17)tetraaza-(9)ruthenahexacyclo(15.2.1.02,7.08,19.010,18.011,16)icosane-9',8''-(7,9)diaza-(8)ruthenatricyclo(7.4.0.02,7)tridecane-9',8'''-(7)aza-(9)aza-(8)ruthenatricyclo(7.4.0.02,7)tridecane-20',8''''-(7)aza-(9)azatricyclo(7.4.0.02,7)tridecane)-1'(19'),1''(9''),1'''(9'''),1''''(9''''),2',2''(7''),2''',2'''',3'',4',4''',4'''',5'',6',6''',6'''',10'',10''',10'''',11'(16'),12',12'',12''',12'''',14',17'-hexacosaene-4'''',12''''-methane dicarboxylate, and 12'''-decyl-3,4'',4''',6,12''-pentanonyl-1',7'',7''',7'''',9'',9''',9'''',17' -dispiro(fluorene-9,20'-(1,8,10,17)tetraaza-(9)ruthenahexacyclo(15.2.1.02,7.08,19.010,18.011,16)icosane-9',8''-(7,9)diaza-(8)ruthenatricyclo(7.4.0.02,7)tridecane-9',8'''-(7)aza-(9)aza-(8)ruthenatricyclo(7.4.0.02,7)tridecane-20',8''''-(7)aza-(9)azatricyclo(7.4.0.02,7)tridecane)-1'(19'),1''(9''),1'''(9'''),1''''(9''''),2',2''(7''),2''',2'''',3'',4',4''',4'''',5'',6',6''',6'''',10'',10''',10'''',11'(16'),12',12'',12''',12'''',14',17'-hexacosaene-4'''',12''''-dicarboxylate-hexafluoro-phosphanuide.    EXAMPLE - Dichloro-p-cymene ruthenium dimer (0.100 g), square planar complex (BiHeBiTbpy) (0.214 g) and N,N- dimethylformamide (50 mL) were added and deaerated to a 200 mL three-necked flask in argon atmosphere. A metal complex (H2dcbpy) (0.08 g) was added to the reaction mixture, deaerated and reacted at 140 degrees C for 21.5 hours. Sodium hydroxide (0.030 g) and ruthenium complex (Ru(dnbpy)2 (BiBzIm)) (0.330 g) were added to obtained reaction liquid, and reacted at 140 degrees C for 6.5 hours. The obtained reaction liquid was filtered, the filtrate was concentrated under reduced pressure, acetone (30 mL) and hexafluoro-phosphate aqueous solution (90 mL) were added to the concentrate, and stirred at room temperature for 1 hour. Then, product is filtered and washed using acetone and hexafluoro-phosphate aqueous solution in ratio of 1:3, to obtain dinuclear ruthenium complex dye (0.61 g).