4-chlorocinnamic acid is widely used in organic synthesis as a building block for the preparation of more complex molecules. It serves as a key intermediate in the production of pharmaceuticals, particularly in the synthesis of compounds with potential anti-inflammatory and anticancer properties. The compound is also utilized in the development of organic light-emitting diodes (OLEDs) due to its ability to form stable and efficient electron-transporting materials. Additionally, it finds application in the field of photopolymerization, where it acts as a photoinitiator to facilitate the curing of coatings and adhesives under UV light. In research, 4-chlorocinnamic acid is often employed in studies related to crystal engineering and supramolecular chemistry, owing to its ability to form well-defined crystalline structures. Its derivatives are also explored for their potential use in agricultural chemicals, such as herbicides and fungicides.