The synthesis and full characterization of new hybrid materials, i.e. benzo-18-crown-6 covalently linked to multi-wall carbon nanotubes - incorporating first and second generation dendrimer approaches - are reported here. Furthermore, the benefit of using these new nanostructured assemblies is demonstrated for solid-contact ion-selective sensor configuration. Both selective recognition and ion-to-electron transduction events take place at the same hybrid nanostructured material. Functionalization of multi-wall carbon nanotubes (MWCNTs) plays a key role in the development of such devices not only allowing an improvement of the analytical parameters such as selectivity and stability but also providing simplicity in the manufacturing stages.