Synthetic receptors (H3, H4, H5 and H6) are designed and synthesised for the first time for theobromine, a xanthine alkaloid used as a diuretic. The synthesis of the receptor H6 is achieved by Co (PPh3) 3Cl-mediated homocoupling of 3-(ethoxycarbonyl) benzyl bromide 12 under mild conditions. New caffeine receptors (H7, H8 and H9) are designed and synthesised. The binding results of theobromine and caffeine (both by NMR and UV ...