2-Methylallyl triphenylphosphonium chloride is primarily used in organic synthesis as a reagent for the preparation of various organic compounds. It is particularly valuable in Wittig reactions, where it facilitates the formation of 1,3-dienes by reacting with carbonyl compounds such as aldehydes and ketones. This chemical is also employed in the synthesis of complex molecules, including natural products and pharmaceuticals, due to its ability to introduce a 2-methylallyl unit into molecular structures. Additionally, it finds application in polymer chemistry, where it can be used to modify or functionalize polymers, enhancing their properties for specific industrial uses.