TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The complex compound contains iron, ruthenium or osmium. The metal catalyst is tetrakis (triphenylphosphine)palladium or dichloro bis(triphenylphosphine)palladium. The protecting group is removed using a base such as lithium hydroxide or triethylamine.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (disclosed): Ruthenium reagent such as ruthenium chloride is dissolved in N,N-dimethylformamide or alcohol solvent, and the pyridyl ring-containing compound of formula (II) and salt which produces an auxiliary ligand are mixed at 40-80 degrees C. The compound (II) is coordinated to the metal atom to obtain the complex compound. Preferred Process: Alternately, the tin compound (B), halogen compound (X) and dihalo compound of formula (XVII) are coupled in presence of metal catalyst, and hydrolyzed to obtain the compound of formula (II). Preferred Definitions:    A=carboxyl, sulfonic acid, suquaric acid, phosphoric acid and/or boric acid, preferably carboxyl, or its salt with organic base;    R1-R3=substituent of formula (III);    Q1,Q2=H;    p=1;    Ar=optionally substituted thiophene ring;    a+b+c=1-3;    b'=1;and    R5'=alkoxyl group, carboxyl group or its salt.    EXAMPLE - (2,6-Dibromopyridin-4-yl)methanol (in g) (1.95) was dissolved in 1,2-dichloroethane (55) and manganese dioxide (4.29) was added and reacted to obtain 2,6-dibromo-pyridine-4-carbaldehyde (21.03). The obtained compound was reacted with 5-bromotriphenylphosphinyl-thiophene-2-carboxylic acid ethyl ester (0.90) in presence of tin compound to obtain tripyridyl thiophene substituted compound. The obtained compound was reacted with tetrakis(triphenylphosphine)palladium (88 mg) to obtain 5-((E)-2-(2,2':6',2''-terpyridin-4'-yl)vinyl)thiophene-2-carboxylic acid (0.38). The obtained compound was dissolved in ethanol and hydrolyzed. The hydrolyzed product and ruthenium chloride trihydrate were stirred under reflux to obtain a complex compound. The photoelectrochemical cell produced using the complex compound had high incident photon-to-current efficiency.