A crystal
growth technique, interfacial cocrystallization, is demonstrated
to be a simple and effective method for preparing multicomponent crystal
forms. The technique is based on the generation of a liquid–liquid
interface between two immiscible solutions of cocrystal-forming compounds,
and its utility is demonstrated through the preparation of polymorphs
and hydrates of caffeine cocrystals, involving three different hydroxy-2-naphthoic
acids, including the formation of some with unexpected compositions
