TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The weak organic base is chosen from carboxylate of alkaline or alkaline-earth metal such as potassium acetate, sodium acetate, cesium acetate, magnesium acetate, calcium acetate, potassium propionate, sodium propionate, cesium propionate, magnesium propionate and/or calcium propionate, carbonate of alkaline or alkaline-earth metal such as lithium carbonate, potassium carbonate, sodium carbonate, cesium carbonate, magnesium carbonate and/or calcium carbonate, and/or bicarbonate of alkaline or alkaline-earth metal such as lithium bicarbonate, potassium bicarbonate, sodium bicarbonate, cesium bicarbonate, magnesium bicarbonate and/or calcium bicarbonate. The weak organic base is potassium acetate.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Property: The molar ratio of disubstituted benzohetero(1,3)diazole compound (V) and weak organic base is 1:3-1:5, preferably 1:2.5-1:4. The molar ratio of heteroaryl compound (VI),(VII),(VIII) or (IX), and catalyst containing palladium is 100:0.1-100:3, preferably 1:0.4-100:2. Preferred Process: The reaction process is carried out in presence of weak organic base, solvent(s) chosen from dipolar aprotic organic solvent and/or halogenated aromatic solvent, and/or catalyst(s) containing palladium. The reaction process is carried out at 80-170 degrees C, preferably 100-150 degrees C for 12-96 hours, preferably 24-72 hours. Preferred Composition: The catalyst containing palladium is chosen from palladium compounds which are in oxidation state of 0 or 2 such as palladium chloride, palladium acetate, bis (dibenzylidene) palladium of formula: (Pd(dba)2) and/or bis(acetonitrile) palladium chloride. The catalyst containing palladium is palladium acetate. The concentration of the disubstituted benzohetero(1,3)diazole compound (V) is 0.01-2 M, preferably 0.02-1 M. The solvent is chosen from N-dimethylacetamide, dimethylsulfoxide, N-methylpyrrolidone, dimethylformamide, chlorobenzene, dichlorobenzene, chloronaphthalene and/or dichloronaphthalene, preferably N-dimethylacetamide and/or chlorobenzene.dba=C6H5CH=CHCOCH=CHC6H5.    TECHNOLOGY FOCUS - POLYMERS - Preferred Property: The polymer (I),(II),(III) or (IV) has weight average molecular weight of 3000-300000 Dalton, preferably 6000-200000 Dalton. EXAMPLE - 4,7-dibromo-2,1,3-benzothiadiazole (in g) (0.294), potassium acetate (0.295), N,N-dimethylacetamide (5 ml), 3,3'-dihexyl-2,2'-dithiophene (0.335) and palladium acetate (1.2 mg) were provided into a 30 ml Pyrex glass reactor with screw stopper. The reactor was provided in an oil bath and pre-heated to 130 degrees C for 72 hours. The color of the reaction mixture became blood-red in 20 minutes and subsequently dark purple at the end of the reaction, cooled to room temperature, and added to methanol (300 ml), to obtain precipitate. The obtained precipitate was washed with mixture of n-heptane (100 ml) and ethyl ether (100 ml). The obtained residue was dissolved in chlorobenzene (5 ml), re-precipitated in methanol (300 ml), and dried at 50 degrees C for 16 hours, to obtain polymer (X) (0.416) in the form of dark purple solid with yield of 89%.