Abstract: We have designed and synthesized a modified calixarene derivative that allows, for the first time, the isolation of a stable cation radical salt that binds a single molecule of nitric oxide deep within its cavity with remarkable efficiency (K_NO >108 M-1), as demonstrated by isolation of a crystalline complex [Calixarene derivatives, NO]+ and its characterization by X-ray crystallography as well as by optical spectroscopy. Furthermore, the ready accessibility of the calixarene cation radical will allow the exploration of its use for developing efficient sensing devices for nitric oxide based on the accompanied color changes. Interactions between aromatic rings via π-stacking are at the origin of many phenomena of organic material science and biological chemistry including the electron transport in DNA through stacked π-bases. Moreover, owing to the synthetic difficulties, the examples of such π-stacked molecules with multiple layers are scarce. Recently discovered multi-layered π-stacked polyfluorenes in which the van der Waals contact between the cofacially-oriented fluorene moieties allows effective electronic coupling amongst them (F1-F6). These stacked p-systems provide the unique opportunity to investigate the electron and energy transport phenomenon through stacked aromatic systems as spacers for the development of (next-generation) conducting wire-like materials for potential applications in the emerging field of molecular electronics and nanotechnology.