[11][12] Diphenylamine derivatives, being electron rich, naturally oxidize to carbazoles when heated in air.

For applications that transition-metal impurities in the final product might inhibit, an alternative is nucleophilic aromatic substitution on dibenzothiophene dioxide.

[16]As carbazoles have a relatively rich UV-visible light spectrum, they see application as pigments[4] and photocatalysts.

[18] Carbazoles stabilize triplet emitters in certain light-emitting diodes;[4] in general, they are electron photodonors (hole acceptors).

[20] Polyvinylcarbazole is useful in the electrical and electronic industries, and certain carbazole novolaks are extremely heat resistant.

The insecticide Nirosan,[4] the cocaine overdose antidote Rimcazole, and the veterinary NSAID Carprofen are all made from carbazole.