To a solution of 1,3-diiodobenzene (50.0 g, 0.152 mol), carbazole (55.0 g, 0.329 mol), Cu (40.0 g, 0.630 mol) and 18-crown-6 (0.5 g) in 1,2-dichlorobenzene (200.0 ml) was added potassium carbonate (150.0 g, 1.085 mol) under nitrogen and stirring. The reaction was carried out at 190° C. for 12 hours. After cooling, the reaction mixture was filtrated. The solid residues were carefully washed with THF. Then, THF and 1,2-dichlorobenzene were evaporated from the combined filtration solution. The crude product was purified by recrystallization from acetone/methanol to give 47.0 g (75.7%) in yield.
