The potential and limits of hydrogen-bonding ionophores and their use in chemical sensors are discussed. Several hydrogen-bonding bis-thiourea ionophores have been found to complex inorganic anions, among them most strongly H2PO4−. Using such ionophores, ion-selective electrodes for chloride and sulfate have been developed. Furthermore, hosts that bind nucleotides with up to five hydrogen bonds have been synthesized. They have been applied in nucleotide selective electrodes, optodes and voltammetric sensors mimicking ion channels.