Room temperature ionic liquids have been employed for the first time as novel and recyclable reaction media for the chemo-selective conversion of aldehydes into their corresponding 1,3-oxathio- and dithioacetal derivatives in excellent yields under mild and neutral conditions. A wide range of functional and protecting groups such as TBDMS, PMB, THP, MOM, benzyl, propargyl ethers, acetonides, carbamates and esters are survived under these reaction conditions. The recovered activated ionic liquids can be recycled for four to five subsequent runs with consistency in activity.