TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation: No preparation method is given. SPECIFIC COMPOUNDS - 37 Compounds (I) are specifically claimed, e.g. 4,7-bis(4,5-bis(cyclohexylmethyl)thieno(3,2-e)benzothiophen-7-yl)-2,1,3-benzothiadiazole of formula (Ia), 4,7-bis(4,5-bis(cyclohexylmethyl)thieno(3,2-e)benzothiophen-7-yl)-2,1,3-benzoxadiazole, 4,7-bis(4,5-bis(cyclohexylmethyl)thieno(3,2-e)benzothiophen-7-yl)-2,1,3-benzoselenadiazole, 4,7-bis(thieno(2,3-f)benzothiophen-6-yl)-2,1,3-benzothiadiazole and 4,7-bis(4,5-diphenylthieno(3,2-e)benzothiophen-2-yl)-2,1,3-benzothiadiazole.    EXAMPLE - Anhydrous tetrahydrofuran (30 ml) and 7,8-dicyclohexylmethylbenzo (1,2-b:4,3-b') dithiophene (0.26 g) were added into a 100 ml of side-arm round bottom flask. The reaction mixture was then cooled to -78 degrees C and then tetramethylethylenediamine (0.21 ml) and solution of lithium n-butyl in hexane (1 ml) were added into the reaction mixture. The yellow colored reaction mixture was kept under stirring, for 30 minutes, at -78 degrees C, Then, 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (0.7 ml) dissolved in anhydrous tetrahydrofuran (5 ml) was added using a drip funnel for 10 minutes. The reaction mixture was slowly brought to 25 degrees C, kept under stirring for further 2 hours and then treated with water (30 ml). After extraction with methylene chloride, the organic phase obtained was washed with water and finally treated with anhydrous sodium sulfate to eliminate traces of humidity. Finally, after removing the solvent at reduced pressure, an oily brown colored product of 2-(4,4,5,5-tetramethyl-1,3,2-dioxoborolan-2-yl)-7,8-dicyclohexylmethylbenzo(1,2-b:4,3-b') dithiophene was obtained. Then palladiumtetrakistriphenylphosphine (8 mg), 4,7-dibromobenzo(c)(1,2,5)thiodiazole (0.056 g), 2-(4,4,5,5-tetramethyl-1,3,2-dioxoborolan-2-yl)-7,8-dicyclohexylmethylbenzo(1,2-b:4,3-b') dithiophene (0.3 g), toluene (15 ml) and aqueous solution of potassium carbonate (7 ml) were introduced into a sidearm round-bottom flask (50 ml) in an inert atmosphere. The reaction mixture was then heated to the reflux temperature of the solvent for 2 hours. The mixture becomes deep red-colored. After cooling the mixture to 25 degrees C, the solvent was removed at reduced pressure to obtain oily red residue was obtained and worked up to give 4,7-bis(7,8-dicyclohexylmethylbenzo (1,2-b:4,3-b')dithiophene) benzo-(c)(1,2,5)thiadiazole (0.085 g).