1,2,7,8-Dibenzcarbazole 1,2:7,8-Dibenzocarbazole 13-Aza-13H-dibenzo[a,i]fluorene 13H-Dibenzo[a,i]carbazole 239-64-5 7H-Dibenzo[a,i]carbazole NSC109911 WLN: T E6 D6 B566 CMJ