3-Aminophenylboronic acid is an aromatic compound featuring both a primary amine group and a boronic acid group on a benzene ring. It is a white to off-white crystalline powder with moderate solubility in water and common organic solvents. As a bifunctional building block, it is a key intermediate in Suzuki-Miyaura cross-coupling reactions, a widely used method for forming carbon-carbon bonds in organic synthesis. Its primary application is as a versatile synthetic intermediate in medicinal chemistry and materials science. The amine group allows for further functionalization (e.g., amide formation, reductive amination), while the boronic acid group enables palladium-catalyzed coupling with aryl halides. This makes it valuable for constructing biaryl structures found in pharmaceuticals, agrochemicals, and organic electronic materials. It is also used in the synthesis of sensors and as a ligand in some catalytic systems. The compound should be handled with care as it may cause skin and eye irritation. It is typically stored under inert atmosphere or refrigerated to maintain stability, as boronic acids can be prone to protodeboronation or oxidation under certain conditions.