TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation: No general method for the preparation of the compound (I) is given in the specification. SPECIFIC COMPOUNDS - 51 Compounds are specifically claimed as the compound (I), e.g. benzimidazo(1,2-a)benzimidazole compounds of formula (IA) to (ID) and (IF).    EXAMPLE - A mixture of 5.00 g 6H-benzimidazolo(1,2-a)benzimidazole, 6.56 g 2-bromodibenzofuran, 5.00 g potassium carbonate and 920 mg copper (I) iodide in 50 ml 1-methyl-2-pyrrolidon (NMP) were stirred under argon at 200 degrees C for 24 hours. The reaction mixture was cooled to 20 degrees C and 100 ml dichloromethane were added. The reaction mixture was filtered on silica gel with dichloromethane. The organic phase was washed with water and dried with magnesium sulfate. The solvent was distilled off. The crude product was decocted with methyl ethyl ketone (MEK) and filtered off to obtain 2.50 g, 28% yield of 5-dibenzofuran-2-ylbenzimidazolo(1,2-a)benzimidazole (a1). About 3.00 g the benzimidazole (a1) was dissolved at 50 degrees C under argon in 15 ml dimethylformamide (DMF). About 2.14 g N-bromosuccinimide was added. The reaction mixture was stirred under argon at 50 degrees C for 18 hours. The precipitated product was filtered off and washed with DMF, ethanol, water and again ethanol to obtain 2.85 g, 78% yield of 2-bromo-5-dibenzofuran-2-yl-benzimidazolo(1,2-a)benzimidazole (b1). About 1.50 g the benzimidazole (b1), 1.50 g 4,4,5,5-tetramethyl-2-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-1,3,2-dioxaborolane, 4.02 g potassium phosphate tribasic monohydrate, 15 ml dioxane, 50 ml xylene and 10 ml water were degassed with argon. About 82 mg 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (sPhos) and 7.4 mg palladium(II) acetate were added. The reaction mixture was degassed with argon and stirred for 22 hours at 100 degrees C under argon. About 40 ml of a 1% sodium cyanide solution were added and the reaction mixture was refluxed for 1 hour, cooled to 20 degrees C and the product was filtered off. The filtered product was washed with water and ethanol and decocted in methyl ethyl ketone to yield 1.05 g, 38.5% of benzimidazo(1,2-a)benzimidazole compound of formula (IA).