This article demonstrates that the interaction of cyclodextrins (CDs) with side chains of water soluble polymers is useful not only as simple models for biological molecular recognition but also as building blocks in nanotechnological applications. In the interaction of CDs with polymer side chains, the selectivity of CDs was enhanced by the steric effect of the polymer main chain and by interaction at multi-sites (i.e., collectivity). Utilizing the interaction of CDs with polymer side chains, stimuli-responsive systems were constructed from simple components. (c) 2006 Elsevier Ltd. All rights reserved.