咪唑啉是由两个双键中的一个还原而衍生自咪唑的一类杂环。已知三种异构体，2-咪唑啉，3-咪唑啉和4-咪唑啉。2和3-咪唑啉含有亚胺中心，而4-咪唑啉含有烯烃基团。2-咪唑啉基团在几种药物中均有发生。
2-(Methylthio)-4,5-dihydro-1H-imidazole
1-(3-(Triethoxysilyl)propyl)-4,5-dihydro-1H-imidazole
2-Ethyl-2-imidazoline
4,5-Dihydro-1H-imidazole-2-sulfonic acid
6-((4R,5S)-5-Methyl-2-oxoimidazolidin-4-yl)hexanoic acid
N-(4,5-Dihydro-1H-imidazol-2-yl)quinoxalin-6-amine
1-(1,3-Bis(hydroxymethyl)-2,5-dioxoimidazolidin-4-yl)-1,3-bis(hydroxymethyl)urea
1-(2-Hydroxyethyl)imidazolidin-2-one
2-(Chloromethyl)-4,5-dihydro-1H-imidazole hydrochloride
2-((Bis(dimethylamino)methylene)amino)-1,3-dimethyl-4,5-dihydro-1H-imidazol-3-ium chloride
2-Butyl-3-((2'-(2-trityl-2H-tetrazol-5-yl)-[1,1'-biphenyl]-4-yl)methyl)-1,3-diazaspiro[4.4]non-1-en-4-one
2-(4-(tert-Butyl)-2,6-dimethylbenzyl)-4,5-dihydro-1H-imidazole hydrochloride
N-(4-(4-Isopropoxybenzyl)phenyl)-4,5-dihydro-1H-imidazol-2-amine
1-(4-Fluorophenyl)-1H-imidazole-2(3H)-thione
(R)-2-Oxoimidazolidine-4-carboxylic acid
4,5-Diphenyl-1H-imidazol-2(5H)-one
2-Methyl-1,3,7-triazaspiro[4.5]dec-2-en-4-one hydrochloride
1-Methyl-1H-imidazol-2(3H)-one
1-Methylimidazolidine-2,4-dione
2-Butyl-1,3-diazaspiro[4.4]non-1-en-4-one hydrochloride
2-Phenyl-4,5-dihydro-1H-imidazole
4-(3-Methyl-2-oxo-2,3-dihydro-1H-imidazol-1-yl)benzoic acid
1,2-Bis(2-(4,5-dihydro-1H-imidazol-2-yl)propan-2-yl)diazene dihydrochloride
2-(4-(Trifluoromethoxy)phenyl)-1,3,8-triazaspiro[4.5]dec-1-en-4-one
4-(4,5-Dihydro-1H-imidazol-2-yl)aniline
(S)-tert-Butyl 1-methyl-2-oxoimidazolidine-4-carboxylate
1-Bromo-3-chloro-5,5-dimethylimidazolidine-2,4-dione
1,3-Bis(hydroxymethyl)-5,5-dimethylimidazolidine-2,4-dione
N-Benzyl-N-((4,5-dihydro-1H-imidazol-2-yl)methyl)aniline hydrochloride
