Since early ‘90s, N-heterocyclic carbene (NHC) ligands have attracted considerable attention worldwide because of their ubiquitous catalytic activities in olefin metathesis and coupling reactions, augmented by the easy access of the ligands and their metal complexes and the stability of the complexes towards moisture, heat, and air. In this article, we will give a concise account of the relevant research activity in chelating N-heterocyclic carbene and their transition metal complexes.