TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (Claimed): 4,7-Bis(7-methyl-2H,3H-thieno(3,4-b)(1,4)dioxin-5-yl)-2,1,3-benzothiadiazole derivatives preparation involves treating 3,4-ethylenedioxythiophene in a reaction vessel with 4,7-dibromo-2,1,3-benzothiadiazole catalyst, a ligand, and a weak base in presence of nitrogen atmosphere at 90 degrees C for 12-48 hours to obtain reaction mixture. The obtained product is mixed with distilled water uniformly. The obtained solution is extracted with methylene chloride and washed with water for three times. The obtained material is dried over anhydrous magnesium sulfate and then precipitated with 3-5 times of methanol to obtain resultant product, which is mixed with succinimide, glacial acetic acid, and solvent in the reaction vessel. The obtain product is stirred with ice cooled water and placed for 24-48 hours for dark reaction. The obtained product is dissolved with 1-methyl-2-pyrrolidone and then processed in a rotary evaporator for methanol recovery. The processed product is dried in vacuum to obtain desired product. Preferred Composition Molar ratio of mixing 3,4-ethylenedioxythiophene with 4,7-dibromo-2,1,3-benzothiadiazole is 2.1:1-2.5:1. Molar ratio of mixing 4,7-dibromobenzo(c)(1,2,5)oxadiazole and 2,1,3-benzothiadiazole is 1:0.003-1:0.1. Molar ratio of mixing ligand and catalyst is 4:1-12:1. Molar ratio of mixing weak base with catalyst is 30:1-80:1. Preferred Components: Ligand is selected from tetrabutylammonium bromide, tricyclohexylphosphine tetrafluoroborate, tricyclohexylphosphine, tributylphosphine, triphenylphosphine or triethylene diamine. Weak base is selected from potassium carbonate, potassium acetate, tetramethylammonium hydroxide solution, tetrabutylammonium hydroxide solution, tetraethylammonium hydroxide, aqueous solution of ammonium, tetrapropylammonium hydroxide, tetrahexylammonium hydroxide solution or tetrabutyl ammonium hydroxide. Solvent is selected from n,n-dimethylformamide, n,n-dimethylacetamide, chloroform or tetrahydrofuran. Catalyst is palladium acetate, (1,1'-bis(diphenylphosphino)ferrocene)dichloropalladium or tetrakis(triphenylphosphine)palladium. 4,7-bis(7-methyl-2H,3H-thieno(3,4-b)(1,4)dioxin-5-yl)-2,1,3-benzothiadiazole derivatives (I) is also represented by compound of formula (II).n=1-10;X=0.05-0.95;R1-R3=H,Br or benzene ring; andAr=group of formulae (III-VI).