An alkynylplatinum(II) terpyridine complex functionalized with polyhedral oligomeric silsesquioxanes (POSS) moieties has been demonstrated to exhibit self-association behavior to give various distinguishable nanostructures with interesting morphological transformation from rings to rods in response to solvent conditions through the stabilization of Pt...Pt and pi-pi stacking interactions as well as hydrophobichydrophobic interactions. These changes can be systemically controlled by varying the solvent composition and have been studied by H-1 NMR, electron microscopy, UVvis absorption, and emission spectroscopies.