1-Bromo-5-iodonaphthalene is primarily used in organic synthesis as a versatile building block for the construction of complex molecules. Its dual halogen substituents make it a valuable intermediate in cross-coupling reactions, such as Suzuki, Sonogashira, and Heck reactions, which are essential in the development of pharmaceuticals, agrochemicals, and advanced materials. The compound is also employed in the synthesis of organic semiconductors and liquid crystals due to its naphthalene core, which provides stability and electronic properties suitable for optoelectronic applications. Additionally, it serves as a precursor in the preparation of dyes and fluorescent probes, leveraging its aromatic structure for light absorption and emission properties.