TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (Claimed): The preparation of (I) comprises (i) reacting 3-bromo-9H-carbazole compounds of formula (II) bis(pinacolato)diboron in presence of 1,1'-bis(diphenylphosphino)ferrocene)palladium(II) chloride catalyst to obtain 3-(4,4,5,5-tetramethyl-(1,3,2)dioxaborolan-2-yl)-9H-carbazole compounds of formula (III); (ii) reacting (III) with tris(4-bromophenyl)amine in presence of tetrakis(triphenylphosphine)palladium(0) to obtain tris(4-(9H-carbazol-3-yl)phenyl)amine compounds of formula (IV); and (iii) reacting (IV) with N-bromosuccinimide in dimethylformamide. Preferred Method: The preparation of (III) comprises dissolving 5-15 pts. potassium acetate, 2-6 pts. bis(pinacolato)diboron and 0.1-0.3 pts. 1,1'-bis(diphenylphosphino)ferrocene)palladium(II) chloride in 100-300 pts. dimethyl sulfoxide under nitrogen atmosphere, stirring at room temperature for 20-30 minutes to obtain solution A, dissolving 1-3 pts. (II) in 5-15 pts. dimethyl sulfoxide to obtain solution B, mixing solution A and solution B under nitrogen atmosphere, heating to 75-90 degrees C, reacting for 20-36 hours, separating and purifying by column chromatography. The step (ii) comprises dissolving 3-9 pts. (III), 1-3 pts. tris(4-bromophenyl)amine and 0.3-0.9 pts. four triphenylphosphine palladium in 20-60 pts. toluene under nitrogen atmosphere, reacting at 95-110 degrees C for 48-72 hours, separating and purifying by column chromatography to obtain (IV). The step (iii) comprises dissolving 1-3 pts. (IV) and 4-12 pts. N-bromosuccinimide in 50-150 pts. N,N-dimethylformamide under nitrogen atmosphere, reacting at 20-30 degrees C for 24-48 hours, separating and purifying by recrystallization. SPECIFIC COMPOUNDS - 12 Compounds (I) are specifically claimed, e.g. tris(4-(6-bromo-N-ethylcarbazol-3-yl)phenyl)amine, tris(4-(6-bromo-N-propylcarbazol-3-yl)phenyl)amine, tris(4-(6-bromo-N-butylcarbazol-3-yl)phenyl)amine, tris(4-(6-bromo-N-pentylcarbazol-3-yl)phenyl)amine and tris(4-(6-bromo-N-hexylcarbazol-3-yl)phenyl)amine.