Cocrystals of metronidazole are described herein. Such cocrystals are a cocrystal of metronidazole with gentisic acid and a cocrystal of metronidazole with gallic acid. Cocrystals of imipramine hydrochloride are also described. Such cocrystals are a cocrystal of imipramine hydrochloride with (+)-camphoric acid, a cocrystal of imipramine hydrochloride with fumaric acid, and a cocrystal of imipramine hydrochloride with 1-hydroxy-2-naphthoic acid.