 Co-crystals are a promising alternative for active pharmaceutical ingredient, API, formulations due to their improved physical chemical and pharmacological properties. Co-formers play a key role in the development of co-crystals, and carboxylic acids are one of the most widely used classes of co-formers. Carboxylic acids can form hydrogen bonds with the APIs, resulting in improved solubility and instability. Additionally, they possess small carbon chains which allow them to be easily incorporated into the APIs. Carboxylic acids are also relatively easy to synthesize and are often available commercially. As a result, carboxylic acids are frequently used as co-formers in co-crystal formulation. This article was authored by Man Singh, Harsh Barua, Vaskuri G.S. Inagajoti and others.