TECHNOLOGY FOCUS - POLYMERS - Preferred Process: In preparing benzohetero(1,3) diazole compound disubstituted heteroaryl groups, the disubstituted benzohetero(1,3) diazole compound having general formula (II) and the heteroaryl compound having general formula (III) are used in molar ratios ranging from 1:2 to 1:20; or the disubstituted benzohetero(1,3) diazole compound having general formula (II) and the heteroaryl compound having general formula (III) are used in molar ratios ranging from 1:4 to 1:12. The process relates to the preparation of a benzohetero(1,3) diazole compound disubstituted with heteroaryl groups having general formula (I) where W represents a sulfur atom, or an oxygen atom; Y represents a sulfur atom, an oxygen atom, or an NR group where R represents a 1-20C alkyl group; Z represents a nitrogen atom, or a CR2 group where R2 is a hydrogen atom, or a CR2 group where R2 and R3 are bound to each other and form a saturated polycyclic system with 6 carbon atoms containing two sulfur atoms; R1, R3, R4 and R5, represent a hydrogen atom; or R1, R4 and R5, represent a hydrogen atom and R3 represents a -COR group where R is a 1-20C alkyl group; or R1, R2 , R4 and R5 represent a hydrogen atom and R3 represents a heteroaryl group optionally substituted with a 1-20C alkyl group. Preferably, the process relates to the preparation of 4,7-di-2-thienyl-2,1,3-benzothiadiazole corresponding to a benzohetero(1,3) diazole compound disubstituted with heteroaryl groups having general formula (I) where W represents a sulfur atom, Y represents a sulfur atom, Z represents a CR2 group and R1-R5 represent a hydrogen atom, and the process comprises reacting 4,7-dibromo-2,1,3-benzothiadiazole corresponding to a disubstituted benzohetero(1,3) diazole compound having general formula (II) where X represents a bromine atom, Y represents a sulfur atom and R3 and R4 represent a hydrogen atom, with a thiophene corresponding to a heteroaryl compound having general formula (III) where W represents a sulfur atom, Z represents a CR2 group where R2 represents a hydrogen atom and R1 and R3 represent a hydrogen atom. The process is carried out in the presence of at least one weak organic base, where the weak organic base is selected from: carboxylates of alkaline or alkaline-earth metals such as potassium acetate, sodium acetate, cesium acetate, magnesium acetate, calcium acetate, potassium propionate, sodium propionate, cesium propionate, magnesium propionate, calcium propionate, or its mixtures; carbonates of alkaline or alkaline-earth metals such as lithium carbonate, potassium carbonate, sodium carbonate, cesium carbonate, magnesium carbonate, calcium carbonate, or its mixtures; bicarbonates of alkaline or alkaline-earth metals such as lithium bicarbonate, potassium bicarbonate, sodium bicarbonate, cesium bicarbonate, magnesium bicarbonate, calcium bicarbonate, or its mixtures; or its mixtures. Preferably, the weak organic base is potassium acetate. The disubstituted benzohetero(1,3) diazole compound having general formula (II) and the weak organic base are used in molar ratios ranging from 1:2.2 to 1:20, preferably from 1:2.5 to 1:4. The process is carried out in the presence of at least one catalyst containing palladium, where the catalyst containing palladium is selected from palladium compounds in oxidation state (0) or (II) such as palladium (II) chloride (PdCl2), palladium (II) acetate (Pd(OAc)2) (preferred), bis (dibenzylidene) palladium (0) (Pd(dba)2 where dba=C6H5CH=CHCOCH=CHC6H5), bis (acetonitrile) palladium (II) chloride (Pd (CH3CN)2Cl2), or its mixtures. The disubstituted benzohetero (1,3) diazole compound having general formula (II), and the catalyst containing palladium are used in molar ratios ranging from 100:0.1 to 100:3, preferably from 100:0.4 to 100:2. Preferably, the disubstituted benzohetero(1,3) diazole compound having general formula (II) is used at a molar concentration ranging from 0.1 M to 1 M, or from 0.15 M to 0.5 M. The process is carried out in the presence of at least one dipolar aprotic organic solvent, where the dipolar aprotic organic solvent is selected from N,N-dimethylacetamide (DMAc) (preferred), dimethylsulfoxide (DMSO), N-methylpyrrolidone (NMP), dimethylformamide (DMF), or its mixtures. It is carried out at a temperature ranging from 80 degrees C to 170 degrees C, preferably from 100 degrees C to 150 degrees C. It is carried out for a time ranging from 30 minutes to 24 hours, preferably from 1 hour to 12 hours. EXAMPLE - No suitable example given.