Used primarily as an intermediate in organic synthesis, especially in the production of pharmaceuticals and agrochemicals. It plays a key role in the preparation of heterocyclic compounds due to its reactivity as an alkylating agent. Commonly employed in the synthesis of imidazoles, thiazoles, and other nitrogen-containing rings found in bioactive molecules. Also utilized in the manufacture of dyes and functionalized polymers where bromine serves as a leaving group for further substitution reactions. Its aldehyde group allows for condensation reactions, making it valuable in forming carbon-carbon bonds. Handle with care due to high reactivity and potential lachrymatory effects.