Lawesson'sreagent acts as an efficient promoter in the solvent-free microwave-assisted synthesis of 2-substituted benzoxazoles from carboxylic acids and 2-aminophenol, and thus, constitutes a general synthetic method for these compounds. This new application of Lawesson'sreagent is valid also for benzothiazoles with very high efficiency level. A variety of aromatic, heteroaromatic and aliphatic carboxylic