Abstract The synthesis of unsymmetrical biaryls with a methylthio group is achieved using the air??stable palladium–phosphinous acid complexes,[(t??Bu) 2P (OH)] 2 PdCl2 (POPd), as the catalyst. A great variety of substituted bromobenzenes having electron??withdrawing and electron??donating functional groups in para and meta positions have been successfully coupled with 3??methylthiophenylboronic acid.