3-Iodo-5-methoxybenzoic acid is primarily utilized in organic synthesis as a building block for more complex chemical structures. It serves as an intermediate in the preparation of pharmaceuticals, particularly in the development of drugs targeting specific receptors or enzymes. Its iodine substituent makes it a valuable candidate for further functionalization through cross-coupling reactions, such as Suzuki or Sonogashira reactions, which are essential in medicinal chemistry. Additionally, the methoxy group enhances its reactivity and selectivity in various synthetic pathways, making it useful in the creation of bioactive molecules or materials with tailored properties.