An efficient and versatile solvent–catalyst system, [HyEtPy]Cl–H₂O-DABCO, has been developed and used in the Morita–Baylis–Hillman reaction. Under the mild reaction conditions, Morita–Baylis–Hillman proceeds very quickly and efficiently. This protocol has notable advantages such as eco-friendliness, ease of work-up and reuse of ionic liquid conveniently, which could help reduce disposal costs and contribute to the development of a new solvent–catalyst system for use in green and continuous chemical processes.