The polystyrene supported palladium-gold (PdÀ Au@PS) catalyst was prepared and well characterized by HR-TEM, EDX, Elemental Mapping, XPS and P-XRD analysis. The PdÀ Au@PS NPs displayed the superior catalytic activity than their monometallic forms. First time, the catalyst was applied for methylthioesterification reaction of aryl iodides with oxalic acid and DMSO as in situ carbon monoxide (CO) and methyl mercaptan (CH 3 SH) precursor. Yet, there is no report available where DMSO has been applied as CH 3 SH source for methylthioester synthesis. The CH 3 SH and CO are likely to poison the metal catalyst whereas in PdÀ Au@PS catalyst, the beneficial inter-electronic interactions between Pd and Au metals makes the catalyst highly reactive, poisoning resistant and recyclable during the transformation. Moreover, the developed protocol exhibits excellent functional group tolerance for various aryl iodides to delivered the desired products in moderate to very good yields.