The interaction between Q<参考文献原文>with β-indoleacetic acid and the methylviologen was studied in aqueous solution with electronic absorption spectroscopy (UV-Vis), fluorescence spectroscopy, 1H NMR spectroscopy and isothermal titration calorimetry (ITC) in details. The authors explored the mode of action, action site and thermodynamic properties of the host-guest system. The electronic absorption and fluorescence spectroscopy data showed that the Q［8］/IAA system and Q［8］/MV2+ system informed 1∶1 inclusion complexes in aqueous solution. ITC results showed that the changes of Gibbs free energy and enthalpy are all negative, it suggested that complex formation was spontaneous and exothermic reaction. Moreover, ITC results for the Q<参考文献原文>and IAA with MV2+ indicate that the association constants of the Q［8］-IAA and Q［8］-MV2+ complexes were (3.22±0.96)×105 L·mol-1 and (3.90±0.91)×106 L·mol-1, respectively. Therefore, the interaction between Q<参考文献原文>and IAA with the MV2+ was a competitive process. This likely occurs because the MV2+ and IAA molecules attempt to occupy the Q<参考文献原文>cavity, which reduces the fluorescence and absorption spectra intensity of Q［8］-IAA because of the formation of a new inclusion complex between Q<参考文献原文>and IAA with MV2+. In addition, with the addition of MV2+ to a Q［8］/IAA complex, 1H NMR results showed that the indole moieties of β-indoleacetic acid and bipyridyl group of methylviologen can be incorporated into Q<参考文献原文>cavities because of electronic transfer MV2+ with PQ in a Q<参考文献原文>cavity with ternary complexes. These results provides the potential applications for the supramolecular self-assembly in cucurbit［n］urils field.