Host-guest interaction and properties of cucurbit[n]uril (n=7,8) with chlorzoxazone

•Complex formation between cucurbit[n]uril(n = 7,8) hosts and chlorzoxazone guest.•The host-guest interaction was studied by single-crystal X-ray diffraction spectroscopy, isothermal titration calorimetry (ITC), UV–vis spectroscopy and 1H NMR spectroscopy.•CHZ and Q[7] form a 1:1 host-guest inclusion complex, and CHZ and Q[8] form a 2:1 host-guest inclusion complex.•After the addition of Q[7], the water solubility of CHZ is improved, and the addition of Q[8] basically does not affect the water solubility of CHZ.•The formation of complex host-guest inclusion complexes will not affect the stability of CHZ itself.