Functionalized carbazole is one of the important topics in drug discovery and material science, which is synthesized in special nitrogen heterocycles. We report here the rhodium(III) catalytic cross-coupling reaction between indolyl nitron and 2-methyldene cyclic carbonate as an allyl substituent. This reaction forms C2-modified carbazole in addition to tandem C-H allylation, exo [3 + 2] cycle, aromaticization, and benzyl oxidation. The synthetic advantage of this protocol is highlighted by the various modifications of C2-modified carbazoles.