3-[4-(benzyloxy)phenoxy]propane isothiourea and 3-[4-(benzyloxy)phenoxy]propanethiol were successfully synthesized by a straightforward reaction. The self-assembled monolayers (SAMs) of 3-[4-(benzyloxy)phenoxy]propane isothiourea and 3-[4-(benzyloxy)phenoxy]propanethiol on the gold electrode as ion-selective electrode showed special capacity in recognition for Ag+.