2-Hydroxyphenylboronic acid is an organoboron compound featuring both a boronic acid group and a phenolic hydroxyl group on the same aromatic ring. This bifunctional structure makes it a versatile building block in organic synthesis, particularly in Suzuki-Miyaura cross-coupling reactions for constructing biaryl systems. Its molecular formula is C6H7BO3. The primary application of 2-hydroxyphenylboronic acid is as a key precursor in the synthesis of various functional materials and complex molecules. Its ability to act as a ligand or a self-assembling unit is exploited in the preparation of covalent organic frameworks (COFs), metal-organic frameworks (MOFs), and supramolecular sensors. These materials find use in gas storage, molecular separation, and chemosensing, especially for diols and sugars, leveraging the reversible esterification of the boronic acid group. Additionally, it serves as an intermediate in the synthesis of pharmaceuticals and agrochemicals. The compound's dual functionality allows for further derivatization, enabling the construction of diverse heterocyclic and macrocyclic structures. It is commercially available and should be handled with care, as boronic acids can be irritants.