Used as a phosphorus-based reagent in organic synthesis, particularly in Wittig reactions to convert aldehydes and ketones into alkenes. Its pyridine-containing structure enhances solubility in polar solvents and can improve selectivity in olefination reactions. Commonly employed in the preparation of conjugated systems and functionalized alkenes for pharmaceuticals, agrochemicals, and materials science. The bromide salt form aids in purification and stability during storage.