Selectivity and sensitivity of PVC membrane electrodes are dramatically influenced not only by a specific receptor but also, especially for neutral ionophores, by additional lipophilic coreceptor. We describe novel systems based on classic cation receptors and a highly lipophilic cobalt bis(1,2-dicarbollide), a bulky, weakly coordinating anion with delocalized charge. The function of the novel coreceptor is demonstrated by the use of dibenzo-18-crown-6 or dicyclohexano-18-crown-6 as ionophore in combination with a classic lipophilic additive and a cobalt bis(dicarbollide). The obtained data show its higher efficiency, which makes this coreceptor suitable for cation detection and development of novel sensors.