Recently,we have reported that 1,1,3,3-tetramethylguanidine(TMG)can be used as a activator to promote the efficient esterification reaction of carboxylic acids with halogenated compounds in polar solvents such as N,N-dimethyl formamide(DMF)and dimethyl sulfoxide(DMSO)at room temperatue[1-3].Herein,we found the TMG promoted esterification reaction can be achieved with excellent yields under solvent-free conditions at room temperature.For example,yield of 98%was obtained when benzoic acid reacted with ethyl iodide under mechanical mixing in 2 hour.Therefore,the purification process becomes more convenient which just needs dissolution and filtration.Moreover,the reaction has a high tolerance to variety of common used functional groups,such as hydroxyl,vinyl,alkynyl,aldehyde and nitro groups.Furthermore,the promoter TMG can be recovered via treated with sodium hydroxide solution.