A new class of monoanionic nitrogen donor ligands imidazolin-2-iminato (ImRN?) is produced from the reactivity of N-heterocyclic carbenes (NHCs) towards organic azides and is isolobally related to imido ligands (RN2-). The imidazolin-2-iminato ligands essentially can be derived by substituting alkyl or aryl group from imido moieties. The proton abstraction from imidazolin-2-imine results in the monoanionic imidazolin-2-iminato ligands that possesses the exocyclic nitrogen, which strongly favors the binding with electrophiles. The nucleophilicity of anionic nitrogen is markedly increased by the charge (positive) delocalization into the five-membered heterocyclic ring. Altering the N-substitutions could meet the necessities for kinetic stabilization of high valent reactive species. These ligands have been slowly cemented the status as a potential alternative for ubiquitous cyclopentadienyl ligand and continued receiving attention. These ligands have progressively accustomed as the ancillary ligands for early transition metals, rare earth elements, or early actinides affording pincer complexes or "pogo stick" type compounds. In this article, the present chemistry of transition metal elements bearing imidazolin-2-iminato/imine ligands is reviewed from the year 2015 to date. © Engineered Science Publisher LLC.