A simple, highly efficient and environmentally friendly method for the synthesis 3-substituted pyrazoles by one pot condensation reaction of substituted cinnamaldehydes and tosylhydrazine in ionic liquid, 1-Butyl-3-methylimidazolium tetrafluoroborate. This method was developed by screening of different imidazolium-based ionic liquids. The reaction system exhibited tolerance with various functional groups and gives good to excellent yields.