Recent advances in the chemistry and applications of N-heterocyclic carbenes.

N-Heterocyclic carbenes, despite being isolated and characterized three decades ago, still capture scientists' interest as versatile, modular and strongly coordinating moieties. In the last decade, driven by the increasingly refined fundamental understanding of their behaviour, the emergence of new carbene frameworks and cogent sustainability issues, N-heterocyclic carbenes have experienced a tremendous increase in utilization across several disparate fields. In this Review, a concise overview of N-heterocyclic carbenes encompassing their history, properties and applications in transition metal catalysis, on-surface chemistry, main group chemistry and organocatalysis is provided. Emphasis is placed on developments emerging in the last seven years and on envisaging future directions.