A spectroscopic experiment is presented that reveals that the hydrophobically end-modified water-soluble polymeric fluorophore, pyrene end-capped poly(ethylene oxide) (PYPY), interacts differently with [alpha], [beta], and [gamma]-cyclodextrins (CD) to form supramolecular inclusion complexes. The emission spectrum of PYPY in aqueous solution shows characteristic dual emission; the pyrene monomer emission and the excimer emission. [alpha]-CD does not affect the absorption and emission spectra of the fluorophore. In [beta]-CD solution, the excimer emission yield decreases with a concomitant enhancement of the monomer emission while the fluorescence spectral observation in [gamma]-CD is qualitatively opposite. The differences in the photophysical behavior of the fluorophore in different CD environments establish different modes of encapsulation of PYPY in CDs with different cavity dimensions. The different modes of encapsulation are explained from the relative dimensions of the pyrene units and the various CD cavities. The cavity of [alpha]-CD is too small to form an inclusion complex with the fluorophore. [beta]-CD cavity has the proper dimension to encapsulate one pyrene unit of the polymer and [gamma]-CD cavity is large enough to include both the fluorophore end-groups in stacked orientation. (Contains 3 schemes and 2 figures.)