3-Iodobenzaldehyde is an aromatic organic compound featuring both an aldehyde group and an iodine atom at the meta position on the benzene ring. It is a pale yellow to beige crystalline solid with a molecular formula of C7H5IO and a molecular weight of 232.02 g/mol. This compound is a versatile and valuable building block in synthetic organic chemistry. Its primary application is as a key intermediate in cross-coupling reactions, most notably Suzuki-Miyaura and Sonogashira couplings, due to the reactivity of the aryl-iodide bond. The aldehyde group serves as a handle for further functionalization, allowing for the construction of complex molecules such as pharmaceuticals, agrochemicals, and materials science compounds. It is frequently used in the synthesis of ligands, liquid crystals, and various heterocyclic systems. As a halogenated benzaldehyde derivative, it requires careful handling. It is typically stored under inert conditions and away from light to prevent decomposition. It is considered an irritant to skin, eyes, and the respiratory system.