TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (disclosed): Mononuclear metal complex of formula (a) reacts with another mononuclear metal complex of formula (b) in presence of solvent and metal salt, and heated to obtain metal complex pigment (c) as metal complex pigment (I).P1-P4=substituent;andBa'=group which forms coupling group (B) with residue of P1 and P2 after coupling.Preferred: The metal complex pigment (I) is preferably of formula (II)-(IV). The photoelectric conversion element further contains pigment of formula: Mz(LL1)m1(LL2)m2(X)m3.Cl' (V).R52-R81=R1, in which R67-R81 have at least one acidic group of formula: -CH=C(-COOH)(-CN);M1,M2=2 H or 1 metal atom;Mz=metal atom;LL1=tridendate or bidendate ligand of formula (viii);LL2=tridentate or bidentate ligand of formula (ix);X=monodentate or bidentate ligand which is coordinated with acyloxy, acylthio, thio acyloxy, thio acylthio, acylamino oxy, thiocarbamate, dithiocarbamate, thiocarbonate, dithio carbonate, trithiocarbonate, acyl, thiocyanate, isothiocyanate, cyanate, isocyanate, cyano, alkythio, arylthio, alkoxy or aryloxy, preferably monodendate or bidendate ligand containing halo, carbonyl, dialkyl ketone, 1,3-diketone, carbonamide, thiocarbonamide or thiourea;m1,m2=0-3;m3=0-2;Cl'=counter ion capable of neutralizing electric charge of pigment (V);R101,R102=carboxy, sulfonic acid group, hydroxy, hydroxamic group, phosphoryl or phosphonyl;R103,R104=substituent;R105,R106=alkyl, aryl or heterocyclyl;d1,d2=0 or more;L1,L2=conjugated chain containing ethenylene, ethynylene, arylene or heteroarylene, and are conjugated with united pyridine ring;a1,a2,b1,b2=0-3;adjacent R103,R104=ring;d3=0 or 1;Za-Zc=nonmetallic atom group capable of forming 5- or 6- membered ring, and optionally containing acidic group;andc=0 or 1. Preferred Definitions:    A,C'=group of formula (ii) or (iii);    R9-R51=R1;    adjacent R9-R47=cyclic structure;    B'=group of formula (iv)-(vii);    a1-a4=1 or more;    D'=S, O or NR;    R=alkyl;and    asterisk=optionally double bond coupled with A or C'.    EXAMPLE - Phthalonitrile (6.5 g), 3,4-dicyanobenzoic acid (0.5 g) and benzene-1,2,4,5-tetracarbonitrile (1.8 g) were stirred at 150 degrees C for 10 hours, and filtered by adding water after cooling to obtain metal complex pigment (I).