The resulting 12,12-dimethyl-10-phenyl-10,12-dihydroindeno[2,1-b]carbazole (7.5 g) and DMF (53 ml) were added to a reaction vessel. N-bromosuccinimide (3.72 g) was added under ice-cooled conditions, and the mixture was stirred for 9 hours and then left for one night. Water (260 ml) was added, and the mixture was subjected to filtration to obtain a brownish white powder of 7-bromo-12,12-dimethyl-10-phenyl-10,12-dihydroindeno[2,1-b]carbazole (8.67 g; yield 94.6%).