Various polyrotaxane modification reactions, such as methylation, hydroxypropylation, tritylation, acetylation, trimethylsilylation, phenylearbamation, dansylation, and nitration, were examined to obtain polyrotaxane derivatives, in which various functional groups were attached to cyclodextrin moieties. Although the nitrate could not be obtained because of significant degradation of the polyrotaxane under the conditions examined, other derivatives were successfully prepared under moderate conditions. The introduction of these functional groups and their degree of substitution were assessed with Fourier transform infrared and NMR spectroscopy. The polyrotaxane derivatives thus obtained were soluble in various organic solvents other than the conventional solvents (dimethyl sulfoxide and aqueous NaOH) used for the unmodified polyrotaxane. That is, the solubility of the polyrotaxane was drastically changed by the examined modification reactions. (c) 2006 Wiley Periodicals, Inc.