Bicyclic diaziridines are important heterocyclic scaffolds, which can be cleaved into 1,3‐zwiterionic species to serve as a versatile precursor in fabricating biologically important N‐hetero‐ and spiro‐cyclic structural frameworks. Owing to their staple architecture, inherent ring strain and ease of synthesis, considerable advancements have been made by employing bicyclic diaziridines towards the construction of heterocyclic systems of biological importance. A significant surge with appreciable efforts in the adoption of such strategies has led to their implementation by the synthetic chemists. This article focuses on the developments in ring expansion of bicyclic diaziridines employed in N‐heterocycle synthesis.