TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (claimed): The nitrogen-containing aromatic compound is obtained by reacting a nitrogen-containing heterocyclic ring compound and fluoro benzophenone compound of formula (2).X,Y',q,p=as mentioned above;andX'=halogen.    TECHNOLOGY FOCUS - POLYMERS - Preferred Structure: The side chain having nitrogen-containing heterocyclic ring group is of formula (D), and the side chain having a sulfonic acid group is of formula (E).Z,Y',R20,q,p=as mentioned above;Y1=Y';Z1=direct bond, -(CH2)l-, -C(CH3)2-, -O-, or -S-;l=1-10;Ar=aromatic group having substituent chosen from -SO3H, -O(CH2)hSO3H, and -O(CF2)hSO3H;h=1-12;m,n=0-10;andk=1-4The polymer consists of repeating structural units of formulae (A,C).Z,Y',R20,q,p,Y1,Z1,Ar,m,n,k=as mentioned above.The polymer further has a structure of formula (B).A,D=-CO-, -SO2-, -SO-, -CONH-, -COO-, -(CF2)l-, -(CH2)l, -CR'2-, cyclohexylidene, fluorenylidene, -O-, or -S-;l=1-10;R'=aliphatic hydrocarbon, aromatic hydrocarbon, or halogenated hydrocarbon;B'=oxygen atom or sulfur atom;R1-R16=H, fluorine, optionally halogenated alkyl, aryl, allyl, nitro, or nitrile;s,t=0-4;andr=0, or 1 or more. Preferred Definitions:    R20=nitrogen-containing heterocyclic ring group derived from pyrrole, thiazole, isothiazole, oxazole, isoxazole, pyridine, imidazole, imidazoline, pyrazole, 1,3,5-triazine, pyrimidine, pyrazine, indole, quinoline, isoquinoline, purine, benzimidazole, benzoxazole, benz thiazole, tetrazole, tetrazine, triazole, carbazole, acridine, quinoxaline, quinazoline, and/or their derivatives.    EXAMPLE - 2,5-dichloro-4'-fluoro benzophenone (in g) (134.6), pyrrole (50.3), potassium carbonate (76), and dehydrated N,N'-dimethylacetamide (840 ml) were heated at 100degreesC for 3 hours in nitrogen atmosphere. The disappearance of raw material was confirmed by thin layer chromatography. The reaction liquid was cooled to room temperature, and added to water (3 L). The product was solidified, filtered, dissolved in toluene (2.5 L), and washed with salt solution. The organic layer was dried, and the solvent was distilled off to obtain a crude product (133.3). The product was purified to obtain 2,5-dichloro-4'-(1-pyrrolyl)benzophenone (125.3) with a yield of 79.3%. 2,5-dichloro-4'-phenoxy benzophenone (185.3), 4,4'-dichloro benzophenone (15.1), 2,5-dichloro-4'-(1-pyrrolyl) benzophenone (7.1), sodium iodide (11.7), bis (triphenyl phosphine) nickel dichloride (11.8), triphenyl phosphine (63), and zinc (94.1) were taken in a flask, and N-methyl-2-pyrrolidone (1000 ml) was added. The contents were reacted for 20 hours, and diluted with N-methyl-2-pyrrolidone (500 ml). The polymerization reaction liquid was poured into hydrochloric acid/methanol solution, and a polymer was precipitated as white powder. The precipitate was filtered, washed and dried, to obtain a polymer (148) having a weight average molecular weight of 154000. The polymer (150) was added to concentrated sulfuric acid (1500 ml) at room temperature, and sulfonated for 24 hours. The reaction mixture was poured into pure water, and a sulfonated polymer was precipitated. The precipitate was washed with pure water, filtered, and dried to obtain a nitrogen-containing-heterocyclic-ring group-containing sulfonated polymer (159) of formula (A) having an ion-exchange capacity of 2.3 meq/g and a weight average molecular weight of 185000. A film obtained using the polymer had excellent heat resistance and a specific resistance of 3.6 Omega.cm.    l-n=not defined.