TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (claimed): Compound (I) is prepared by adding cyanobisphenol monomer, 2-chloro-5-nitrobenzonitrile, anhydrous potassium carbonate, dimethylformamide (DMF) and toluene to a three-necked flask containing water under nitrogen protection, stirring and reacting at 130-135 degrees C for 2-3 hours to remove water and toluene, heating to 148-152 degrees C and continuously stirring for 3-4 hours, pouring the reaction product into ice water-ethanol mixture to obtain large yellow precipitate, filtering and repeatedly washing with pure water, and vacuum drying at 80 degrees C to obtain dicyanodinitro monomer; and adding dicyanodinitro monomer and 10% palladium-on-carbon catalyst in anhydrous ethanol to a three-necked flask under nitrogen protection, dropping hydrazine hydrate, refluxing for 4 hours, filtering while hot, pouring filtrate into ice to obtain yellow precipitate, recrystallizing yellow precipitate with 1:1 water-ethanol mixture at 80 degrees C, and vacuum drying. The mole ratio of cyanobisphenol monomer, 2-chloro-5-nitrobenzonitrile and anhydrous potassium carbonate is 1: 2.05-2.2:1.02-1.2. The volume ratio of toluene and DMF is 1:3-4. The amount of DMF is 4-6 times the total amount of cyanobisphenol monomer 2-chloro-5-nitrobenzonitrile and anhydrous potassium carbonate. The ratio of dicyanodinitro monomer and 10% palladium-carbon catalyst is 25-30:1. The solid-liquid ratio of dicyanodinitro monomer, 10% palladium-carbon catalyst in anhydrous ethanol and hydrazine hydrate is 1:20-30:2-4.    TECHNOLOGY FOCUS - POLYMERS - Preparation (claimed): Compound (II) is prepared by (i-a) dissolving compound (I) and dianhydride monomer in N,N-dimethylacetamide (DMA), stirring at room temperature for 20 hours, casting obtained viscous polyamide acid solution on a clean glass plate, and drying at 80 degrees C for 4 hours; reacting at 120 degrees C for 0.5 hour, at 150 degrees C for 0.5 hour, at 180 degrees C for 0.5 hour, at 210 degrees C for 0.5 hour, and at 250 degrees C for 1 hour; and cooling to room temperature to obtain dicyanopolyimide film; or (i-b) dissolving dicyanodiamino monomer in DMA, adding dianhydride monomer after dicyanodiamino monomer is completely dissolved, stirring at room temperature for 20 hours, adding 1.2:1 pyridine-acetic anhydride mixture, stirring for 2 hours, pouring obtained viscous solution into anhydrous ethanol for precipitation, crushing, filtering, and extracting to obtain solid dicyanopolyimide; and (ii) dissolving polyimide solid in organic solvent at solid-liquid ratio of 1:10-15, stirring for 4-8 hours, filtering and casting filtrate on glass sheet, drying at 60 degrees C for 10 hours, heating to 120 degrees C, and vacuum drying for 4-6 hours. Compound (III) is prepared by adding 2,2'-disulfonate-4,4'-diaminodiphenyl ether, triethylamine, m-cresol and compound (I) to a three-necked flask under nitrogen protection, sequentially adding 1,4,5,8-naphthalene dicarboxylic acid anhydride and benzoic acid while stirring, reacting at 80 degrees C for 4 hours, heating to 175 degrees C for 15 hours, reacting at 195 degrees C for 3 hours, cooling to 100 degrees C, pouring obtained highly viscous dicyanopolyimide solution to acetone, crushing obtained dicyanopolyimide brown fiber, filtering, extracting with acetone for 10 hours, and drying at 100 degrees C for 10 hours to obtain granular sulfonated dicyanopolyimide; and dissolving granular sulfonated dicyanopolyimide in organic solvent, stirring for 4-8 hours, filtering and casting filtrate on glass plate, drying at 60 degrees C for 10 hours, heating to 120 degrees C for 4-6 hours, and vacuum drying. The mole ratio of dicyanodiamino monomer and dianhydride monomer is 1:1. The solid-liquid ratio of dicyanodiamino monomer and dianhydride monomer to DMA is 1:6-15. The ratio of pyridine-acetic anhydride mixture to dicyanodiamino monomer is 1:1. The mole ratio of 2,2'-disulfonate-4,4'-diaminodiphenyl ether, triethylamine, compound (I), 1,4,5,8-naphthalene dicarboxylic acid anhydride and benzoic acid is 0-1:2.4-2.6:0-1:2:2.8. The ratio of m-cresol to solid is 10-15:1. The solid-liquid ratio of granular sulfonated dicyanopolyimide and organic solvent 1:10-15. The organic solvent is DMA, dimethylsulfoxide, or N-methylpyrrolidone.