TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation: Bipyridyl ligand and dichloro (p-cymene) ruthenium (II) dimer (as transition metal), are reacted. Ammonium isothiocyanate and N-butyl lithium and dimethyl formamide are reacted with the resulting reaction solution. 4,4'-dimethyl-2,2'-bipyridine and p-dialkyl amino benzaldehyde are reacted with the resulting mixture. The reaction solution is dehydrated using paratoluene sulfonic acid pyridinium salt, to obtain transition metal complex. Preferred Definitions:    A=iso thiocyanato group;    M=bivalent ruthenium ion;    Ar=group of formula (c1);    L2=group of formula (b2);    R4,R5=Z, preferably H, or 1-16C alkyl optionally substituted by fluoro group, where at least one of R4 and R5 is alkyl;    X=oxygen or sulfur;    L1=group of formula (a2);and    R1,R2=defined above.    EXAMPLE - Dimethyl formamide solution (10 ml) of dichloro (p-cymene) ruthenium (II) dimer (in g) (0.0747) and 4,4'-bis (2-(5-hexyl-2-thienyl)vinyl)-2,2'-bipyridine (0.15) was heated for 10 minutes at 60degreesC in nitrogen atmosphere. 2,2'-bipyridine-4,4'-dicarboxylic acid (0.12) was added to the reaction solution. The resulting mixture was heated at 150degreesC for 10 minutes and cooled at 100degreesC. Ammonium thiocyanate (0.8) was added to the cooled solution, and reacted for 10 minutes at 120degreesC. Then, vacuum distillation of dimethyl formamide was carried out. Water (80 ml) was added to the residue, and insoluble substance was collected. The resulting product was washed using water and diethyl ether. The crude product was dissolved in methanol with hydrated tetrabutyl ammonium, and purified. 0.2M nitric acid was added to the resulting product, and deposit was obtained. The resulting deposit was vacuum-dried at room temperature, to obtain ruthenium complex. The obtained ruthenium complex had high molecular extinction coefficient in visible ultraviolet region and favorable absorbency, and provided photoelectric converting elements having excellent durability and photoelectric conversion characteristics.