Used in organic synthesis as an acylating agent, particularly in the production of pharmaceuticals and fine chemicals. It serves as a reagent for introducing crotonyl groups into molecules, which is useful in the development of active pharmaceutical ingredients. Also employed in polymer chemistry to modify resins and create specialty polymers with improved thermal or mechanical properties. Its reactivity makes it valuable in the preparation of intermediates for agrochemicals and dyes. Requires careful handling due to its moisture sensitivity and potential irritancy.