N‐Fused heterocycles are of particu

N‐Fused heterocycles are of particular use and upmost importance in multiple fields. Herein, we disclose a conceptually new approach for the rapid assembly of N‐fused heteroarenes from alkenes. A portfolio of strategically designed heterocyclization reagents are readily prepared for the cascade reaction. A plethora of N‐fused heteroarenes including seven types of heterocyclic core are furnished. The protocol features a broad functional‐group compatibility and high product diversity, and provides a practical tool for late‐stage heteroarene elaboration.