The synthesis of a novel covalently immobilized crown ether based potassium ionophore is presented. Apart from previously proposed methods for the preparation of PVC linked ionophores based on the chemical modification of functionalized PVC polymers, the hereby proposed procedure involves the direct copolymerization of a suitable derivative of the bis-crown ether type potassium ionophore (BME 44) and vinyl chloride monomer. The analytical performance of the potentiometric ion selective electrodes incorporating the PVC bound ionophore were optimized and determined. Compared with electrodes based on other bis-crown ether type immobilized potassium selective ionophores a slightly improved logK(K, Na)(Pot) and a longer lifetime was found. Spectral imaging and chronoamperometry were used to study the mobility of different bis-crown ether derivatives in plasticized PVC membranes.