NOVELTY - A dihalo biphenyl compound (I) is new.    USE - New dihalo biphenyl compound is used for manufacturing polymer used for forming sulfo group-containing polyarylene (all claimed) used as polymer electrolyte for polymer electrolyte fuel cell.    ADVANTAGE - The polymer efficiently provides sulfo group-containing polyarylene with high molecular weight.    DETAILED DESCRIPTION - A dihalo biphenyl compound of formula (I) is new.    A=-N(-R3)-R2-N(-R3)- or -O-R2-O-;    R2=1-20C bivalent hydrocarbyl in which H is optionally substituted by fluoro, 1-20C alkoxy, 6-20C aryl, 6-20C aryloxy, 2-20C acyl or cyano;    R3=H or 1-20C monovalent hydrocarbyl in which H is optionally substituted by fluoro, 1-20C alkoxy, 6-20C aryl, 6-20C aryloxy, 2-20C acyl or cyano;    R1=fluoro, 1-20C alkyl, 1-20C alkoxy, 6-20C aryl, 6-20C aryloxy, 2-20C acyl or cyano, in which H is optionally substituted by fluoro, cyano, 1-20C alkoxy, 6-20C aryl or 6-20C aryloxy;    X1=chloro, bromo, or iodo;    or R1+R1=ring;and    k=0-3.    INDEPENDENT CLAIMS are included for the following:    (1) manufacture of dihalo biphenyl compound (I);    (2) polymer, which has structural unit of formula (IV) derived from dihalo biphenyl compound;    (3) manufacture of polymer, which involves polymerizing dihalo biphenyl compound (I), aromatic compound of formula: X2-(((Ar1-Y1)a-Ar2-Z1-((Ar3-Y2)b-Ar4-Z2)c)n(Ar1-Y1)a-Ar2)-X2 (VII) and aromatic compound of formula: X3-(Ar5)-X3 (VIII), in presence of nickel compound; and    (4) manufacture of sulfo group-containing polyarylene, which involves hydrolyzing the polymer, and has structural unit of formula (IX).    a-c=0 or 1;    n=2 or more;    Ar1-Ar5=bivalent aromatic group in which hydrogen atom is optionally substituted by 1-20C alkyl, fluoro, cyano, or 1-20C alkoxy or 2-20C acyl (both optionally substituted by fluoro, cyano, 1-20C alkoxy, 6-20C aryl or 6-20C aryloxy), or 6-20C aryl or 6-20C aryloxy (both optionally substituted by fluoro, cyano, 1-20C alkoxy or 6-10C aryloxy);    X2,X3=X1;    Y1,Y2=single bond, -CO-, -SO2-, -C(CH3)2-, -C(CF3)2-, or fluorene-9,9-diyl;and    Z1,Z2=-O- or -S-.