Book excerpt: In recent years, the fast development of the supramolecular host-guest interactions has attracted significant attention. Based on the dynamic interaction between macrocyclic structures and a variety of matching guests, two chemical entities can be conveniently bond together without the need for further reactions. These features also facilitate straightforward modifications of polymers to create more advanced materials with tunable properties or additional functionalities. Most commonly cyclodextrins have been used as supramolecular hosts and opened up exiting new opportunities in the field of polymer chemistry. More recently, a new generation of macrocycles, the pillar[n]arenes was established which not only broadened the range of guests but also allowed the facile modification of their exterior. The early reports on these materials certainly prove their potential, however several aspects concerning the building of polymer nanostructures based on such supramolecular host-guest complexes, as well as their therapeutic applications as smart nanocarriers remain unexplored. The overall aim of this thesis was therefore to investigate the capacities of pillar[n]arene based materials in polymer chemistry which includes the formation of supramolecular quasi-block copolymers by host-guest interactions and their formulation into nanoparticles, the tuning of thermoresponsive polymers, as well as using pillar[5]arene to functionalize preformed nanoparticles or nanogels, respectively, for therapeutic applications. This thesis demonstrates the tremendous potential of supramolecular modifications based on pillar[5]arenes for the advancing existing polymer designs and nanostructures. It comprises a detailed characterization of all prepared nanostructures, provides novel aspects to the formulation of smart nanostructures, and examines their suitability for encapsulation and release of pharmaceutical active ingredients.