TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The nickel compound is nickel halide.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The polymerization reaction of monomer composition containing dihalo biphenyl compound is performed under coexistence of nitrogen-containing bidentate ligand and zinc. The dihalo biphenyl compound (III) is obtained by coupling dihalo benzene compound of formula (v) in presence of copper metal and copper salt under coexistence of amine compound containing at least two tertiary amino group in a molecule.X1=chloro, bromo or iodo.Preferred Composition: The content of nickel compound is 0.01-5 mol with respect to 1 mol of monomer in monomer composition.    TECHNOLOGY FOCUS - POLYMERS - Preparation (claimed): A monomer composition containing dihalo biphenyl compound of formula (III) is polymerized in presence of nickel compound, to obtain polyarylene. Preferred Composition: The repeating unit (II) is of formula (i), (ii), (iii) or (iv).j=1-4;m=0-3;X=halo;Y'=-OM' or -OM+;M+=cation;M'=optionally substituted 1-20C alkyl;andi=0-2.Preferred Process: The repeating unit (I) is obtained by polymerizing monomer composition containing dihalo biphenyl compound (III). EXAMPLE - 130 g 1-Bromo-4-chloro-2-(trifluoromethyl)benzene, 64 g copper powder, 4.8 g monovalent copper iodide, 3.9 g 2,2'-bipyridyl, and 520 g N-methyl-2-pyrrolidone were mixed, and reacted at 120 degrees C for 7 hours under nitrogen atmosphere. The obtained reaction mixture was cooled at 25 degrees C. 720.8 g 19% Hydrochloric acid and 720 g toluene were added into resultant mixture, stirred and liquid separation was carried out. The toluene layer obtained after liquid separation was washed using water and 5 % sodium hydroxide aqueous solution, and dried with sodium sulfate. The obtained mixture was filtered, sodium sulfate was separated, and obtained filtrate was concentrated and dried, to obtain 79.7 g crude product. The crude product was purified, concentrated and dried, to obtain 70 g 4,4'-dichloro-2,2'-bis(trifluoromethyl)biphenyl with yield of 77.8%.