Used as a key reagent in organic synthesis, particularly for the preparation of enamines and enol ethers. It serves as a methylenating agent, enabling the conversion of active methylene compounds into their corresponding vinyl derivatives. Commonly applied in the synthesis of pharmaceuticals, agrochemicals, and fine chemicals due to its efficiency in forming carbon-carbon double bonds. Also utilized in the production of dyes and intermediates where selective methylation or condensation reactions are required. Its role in the Vilsmeier-Haack type reactions further extends its utility in formylating aromatic and heterocyclic compounds.