The photophysics of an alkaloid harmaline in aqueous buffer solution and in the presence of cucurbit[7] uril have been studied. The photophysical properties of harmaline were modulated several folds due to addition of cucurbit[7] uril in the aqueous buffer solution. We have observed quenching of fluorescence intensity of harmaline with gradual addition of CB7. Isothermal titration calorimetry technique ( ITC) was performed to get an idea about the thermodynamic parameters involved in the complexation process. From ITC, we observed that the complexation process was exothermic in nature and enthalpy driven process. (C) 2017 Elsevier B.V. All rights reserved.