The novel efficient procedure has been developed for the oxathioacetalization of carbonyl compounds and 2-mercaptoethanol at room temperature under solvent-free condition. The results showed that the novel multi-SO3H functionalized ionic liquid was very efficient for the reactions with the good to excellent yields in short time. Operational simplicity, without need of any solvent, room temperature, low cost of the catalyst used, high yields, applicability to large-scale reactions, reusability and chemoselectivity are the key features of this methodology.