Indolo[3,2‐b]carbazole is a molecule of great biological significance, as it is formed in vivo after consumption of cruciferous vegetables. The reaction of 1H‐indole and various aldehydes in the presence of a catalytic amount of N,2‐dibromo‐6‐chloro‐3,4‐dihydro‐2H‐benzo[e][1,2,4]thiadiazine‐7‐sulfonamide 1,1‐dioxide as an efficient and homogeneous catalyst in acetonitrile at 50°C produces 6,12‐disubstituted 5,7‐dihydroindolo[2,3‐b]carbazole with an in good to excellent yield. The presented technique offers a fast and robust method, by the use of inexpensive commercially available starting materials toward 6,12‐disubstituted 5,7‐dihydroindolo[2,3‐b]carbazole. A new anomeric‐based oxidation was kept in mind for the final step of the indolo[2,3‐b]carbazoles synthesis. The suggested anomeric‐based oxidation mechanism was supported by experimental and theoretical evidences.