In this study, we investigated zinc-tetraphenylporphyrin/gamma-cyclodextrin complex formation based on absorption, on fluorescence and circular dichroism spectroscopy, and on fluorescence decay measurement. When the cyclodextrin concentration increased, a new absorption and fluorescence peak appeared and then circular dichloism spectra suggested a chairal aggregate formation. These results indicated that the addition of gamma-CD enhanced J-aggregate formation. Themorphology of the obtained aggregates was directly observed by SEM and TEM, which showed one-dimensional rod-like structures of 30 nm in diameter and ca. 200 nm in length.