TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The inert gas protective atmosphere is nitrogen and/or argon gas.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (claimed): The compound (I) is prepared by adding bromine-containing compound of formula (A) and tin-containing compound of formula (B) at molar ratio of 1:1.1-1.5 with organic solvent and catalyst under inert gas protective atmosphere, dissolving, subjecting to Stille coupling reaction at 60-120 degrees C for 24-72 hours, separating, and purifying. Preferred Components: The catalyst is tetrakis(triphenylphosphine)palladium or bis(triphenylphosphine)palladium dichloride; or mixture of organic palladium and organic phosphine ligand at molar ratio of 1:2-20. The organic palladium is tris(dibenzylideneacetone)dipalladium. The organic phosphine ligand is tri(o-methylphenyl)phosphine. The organic solvent is tetrahydrofuran, N,N-dimethylformamide and/or toluene. Preferred Method: The separation and purification steps are carried out by evaporating reaction solution excessive solvent under reduced pressure, dropping into methanol to carry out sedimentation, filtering, washing with methanol, drying, eluting with chloroform eluent through alumina column chromatography, steaming to remove organic solvent, adding methanol to carry out sedimentation, filtering, subjecting to Soxhlet extraction with acetone, adding methanol to carry out sedimentation, and filtering. The compound (A) is prepared by:(A) adding lithium chloride, 2,5-dibromo-1,4-diiodobenzene, palladium catalyst, cuprous chloride, 3-bromothiophene tin compound and reaction solvent into reaction flask, stirring at room temperature for 1-2 hours, heating to 50-55 degrees C for 3-4 hours under inert gas protective atmosphere, cooling to room temperature, filtering resulting solid to obtain crude 2,2'-(2,5-dibromo-1,4-phenylene)bis(3-bromothiophene), and purifying;(B) adding sodium tert-butoxide, 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl, alkylamine and palladium catalyst, dissolving in solvent under inert gas protective atmosphere, refluxing while stirring for 2-3 hours, cooling to room temperature, filtering to remove solids, extracting filtrate to obtain organic phase, washing with water and saturated brine, drying, filtering, rotary evaporating, and purifying through silica gel column chromatography to obtain N-alkylated pyrrole indole and dithiophene derivative; and(C) adding tetrahydrofuran or N,N-dimethylformamide, cooling to - 78 degrees C, slowly dropping N-bromosuccinimide with tetrahydrofuran or dissolved N,N-dimethylformamide, continuously stirring while reacting for 0.5-1 hour, quenching with water, extracting with dichloromethane, drying, and purifying through silica gel column chromatography.The molar ratio of 2,5-dibromo-1,4-diiodobenzene and 3-bromothiophene tin compound is 1:1.1-1.5. The molar ratio of 2,5-dibromo-1,4-diiodobenzene and lithium chloride is 1:6-1:6.2. The molar ratio of 2,5-dibromo-1,4-diiodobenzene and cuprous chloride is 1:5-1:5.2. The 0.01 -5 wt.% palladium catalyst is bis(triphenylphosphine)palladium dichloride or tetrakis(triphenylphosphine)palladium. The solvent is tetrahydrofuran, N,N- dimethylformamide or toluene. The molar ratio of 2,2'-(2,5-dibromo-1,4-phenylene)bis(3-bromothiophene) and amine is 1:3-4. The dosage of sodium tert-butoxide is 5-8 times. The dosage of 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl is 0.2-0.3 times. The palladium catalyst is bis(triphenylphosphine)palladium dichloride, tris(dibenzylideneacetone)dipalladium or tetrakis(triphenylphosphine)palladium. The 5-10 wt.% solvent is xylene or toluene. The molar ratio of N-alkylated pyrrole indole and dithiophene derivative and N-bromosuccinimide is 1:2.2-3.