B-(3,5-Dichloro-4-hydroxyphenyl)boronic acid is an aromatic boronic acid derivative characterized by a central phenyl ring substituted with two chlorine atoms at the 3- and 5-positions, a hydroxyl group at the 4-position, and a boronic acid functional group. This specific substitution pattern imparts unique electronic and steric properties to the molecule. Its primary application is as a key synthetic building block in materials science, particularly in the synthesis of organic electronic materials. It serves as a crucial monomer or intermediate in Suzuki-Miyaura cross-coupling reactions for constructing complex conjugated organic molecules used in Organic Light-Emitting Diodes (OLEDs) and other optoelectronic devices. The electron-withdrawing chlorine atoms and the hydroxyl group can be utilized to fine-tune the HOMO-LUMO energy levels, solubility, and intermolecular interactions of the resulting polymers or small molecules, which are critical for device performance. As a boronic acid derivative, it is also a versatile reagent in organic synthesis for constructing biaryl linkages. It should be stored under inert conditions to prevent protodeboronation and handled with standard precautions for boronic acids.