TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: The organic palladium catalyst is tris (dibenzylideneacetone) palladium; or a mixture of bis(triphenylphosphine)palladium(II) dichloride and tetrakis (triphenylphosphine) palladium. The molar ratio of the palladium catalyst and compound (I) is 1:2000-1:2.    TECHNOLOGY FOCUS - POLYMERS - Preparation (claimed): Preparation of (I) comprises under a protective gas atmosphere, carrying out Stille coupling reaction of dithienothiophene compound of formula (II) and a substituted naphthalene compound of formula (III), in the presence of an organic palladium catalyst in an organic solvent; and separating and purifying. Preferred Method: The Stille coupling reaction is carried out at 30-130 degrees C for 24-72 hours. Separating and purifying is carried out by adding methanol, precipitating, filtering, drying using diethyl chlorobenzene to dissolve aqueous solution of diethyl sodium dithiocarbamate, stirring overnight at 80 degrees C, washing organic phase using alumina column chromatography, eluting with chloroform, removing the organic solvent after precipitation with methanol, and extracting with acetone, precipitating with methanol, filtering, and drying. Compound (II) is prepared by adding n-butyllithium to a - 78 degrees C 2,6-dibromobisthieno(3,2-b:2',3'-d)thiophene in tetrahydrofuran solution, where the molar ratio of 2,6-dibromobisthieno(3,2-b:2',3'-d)thiophene and n-butyllithium is 1: 3, heating to room temperature while stirring, adding trimethyl chloride, cooling to - 78 degrees C for 0.5 hours, raising the temperature to room temperature, reacting for 24-72 hours, where the molar ratio of trimethyl chloride and 2,6-dibromobisthieno(3,2-b:2',3'-d)thiophene is 1: 1, separating, and purifying. Compound (III) is prepared by adding a primary amine of formula (NH2-R1) to 2,6 - dibromo-1 ,4,5,8 - naphthalenedicarboxylic acid anhydride, under the protection of a protective gas, refluxing for 12-18 hours, where the molar ratio of NH2-R1 to 2,6 - dibromo-1 ,4,5,8-naphthalenedicarboxylic acid anhydride is 10: 1, separating, and purifying.