Benzo[b]thiophen-3(2H)-one and naphto[2,1-b]thiophen-3(2H)-one was condensed in the presence of barium oxide on potassium fluoride with aromatic aldehydes to give 2-arylméthylidène-1-benzothiophèn-3-ones (1) (thioaurones) without solvent under focused microwave irradiation. It is a efficient catalyst basic in knoevenagel condensation reaction