Imidazolines are a chemical substance group in the field of heterocyclic compounds and belong to the group of Azoline. Its members are five-membered cyclic unsaturated organic compounds which carry exactly two non-adjacent nitrogen atoms in the ring skeleton. They are derived from the imidazoles by hydrogenation of a double bond from and are isomeric to the pyrazolines. There are three basic structures of the imidazolines, the isomer each other and which differ by the position of the double bond.

Imidazolines can form stable carbenes. This substituted imidazole with sodium hydride and potassium tert- butoxide can be reduced to two nitrogen atoms. The resulting carbenes are stable and are referred to as Arduengo carbenes. These carbenes can be used for example as ligands of Grubbs catalysts.