2-[1-(4-Chlorobenzoyl)pyrrolidin-2-yl]-4,4,5,5-tetramethyl-4,5-dihydroimidazole-1-oxyl-3-oxide

In the title compound, C18H23ClN3O3, the imidazole ring system has an envelope conformation, whereas the nitronyl nitroxide unit displays a half-chair or twisted conformation. In the crystal, C—H...O hydrogen bonds build up a three-dimensional network.