A cocrystal may be defined as a multi-component crystal in which two or more molecules that are solid under ambient condition coexist through hydrogen bonds. Definition of cocrystal can be made flexible to accommodate solvent (liquid) or gas as the second (third) component and the supramolecular interaction be not limited to hydrogen bonds but include other intermolecular interactions, e.g. halogen bonds, π-π stacking or any other non-covalent interactions. Cocrystals that are formed between an Active Pharmaceutical Ingredient (API) and a non-toxic chemical or GRAS (Generally Regarded as Safe) molecule to the human body is called as Pharmaceutical Cocrystals. Several problems encountered in pharmaceutical industries with APIs, in terms of their solubility, dissolution rates, and stability can be surmounted without the need to make or break covalent bonds of the drug molecule by making appropriate cocrystal.

Supramolecularsynthons in phenol–isonicotinamide adducts