TECHNOLOGY FOCUS - POLYMERS - Preparation (Claimed): The preparation of (I) comprises performing Stille coupling reaction of substituted 5,5'-bis-tributylstannanyl-(2,2')biselenophenyl compounds of formula (II) and substituted 1,6-dibromo-8,11-diselena-7,9,10,12-tetraaza-dicyclopenta(c,g)phenathrene compounds of formula (III) in a molar ratio of 1:1.5-1.5:1 under a protective gas atmosphere in an organic solvent containing an organic palladium catalyst, and separating and purifying. Preferred Components: The organic palladium catalyst is tris(dibenzylideneacetone)dipalladium(0), tetrakis(triphenylphosphine)palladium(0) or bis(triphenylphosphine)palladium dichloride. The molar ratio of the organic palladium catalyst and (II) is 1:2000-1:5. Preferred Method: The Stille coupling reaction is performed at 50-120 degrees C for 6-100 hours. The separation and purification of (I) comprises adding mixture of toluene and deionized water to the reaction solution, extracting, collecting organic phase, removing at least a portion of the organic solvent, adding ethanol to precipitate, filtering, drying, dissolving obtained powder in chloroform, performing chromatography using neutral alumina, removing the organic solvent, precipitating with methanol, filtering, extracting obtained solid with acetone, collecting the acetone solution, precipitating with methanol and filtering. (II) are prepared by adding 5,5'-dibromo-(2,2')biselenophenyl compounds of formula (IV) into tetrahydrofuran under protective gas atmosphere, adding n-butyllithium at -78 degrees C, where the molar ratio of (IV) and n-butyllithium is 1:2, stirring and reacting for 1-2 hours, adding tributyltin chloride at -78 degrees C, where the molar ratio of tributyltin chloride and (IV) is 2:1, reacting at -78 degrees C for 1 hour, heating the reaction mixture to room temperature, stirring for 6 hours, adding saturated aqueous sodium chloride solution to terminate the reaction, extracting the reaction solution was with anhydrous diethyl ether, drying the obtained organic phase, filtering, removing the solvent, and performing column chromatography using neutral alumina. (III) are prepared by performing ring closure reaction of 7,7'-dibromo-5,5'-diiodo-(4,4')bi(benzo(1,2,5)selenadiazolyl) (V) with alkyne compounds of formula (R1-CC-R2) (VI) in a molar ratio of 1:2 in an organic solvent containing an organic base and a catalyst, separating and purifying, where the organic base is tributylamine and the catalyst is palladium acetate. The separation and purification of (III) comprises extracting the reaction solution obtained by ring closure reaction successively with water and dichloromethane, collecting organic layer, drying over anhydrous sodium sulfate, filtering, distilling off the solvent and performing silica gel column chromatography.