A new NMR technique, namely paramagnetic suppression spectroscopy (PASSY), has been used to study the oxidation-state dependent structural conformation and supramolecular function of redox-active rotaxanes and catenanes in solution and at the surfaces of nanoparticles. Specifically, this technique has been used to study the structural conformation and supramolecular function in solution of a redox-active [2]rotaxane and the corresponding radical cation formed by a one-electron reduction. The findings of this and related studies provide important insights into the design of nanoscale devices based on rotaxanes and catenanes.