The structure and dynamics of a charge transfer drug molecule 4,4-diaminodiphenyl sulfone (dapsone) inside the cyclodextrins (alpha-, beta, gamma-CDs) in aqueous solution have been studied using steady state and time-resolved emission spectroscopies. The quantum yields were significantly larger in the presence of beta- and gamma-CDs than in water, wherein the beta-CD confinement shows the largest effect. The results reveal that dapsone forms 1:1 complexes with both beta-CD and gamma-CD. At higher concentrations of beta-CD a combination of 1:1 and 1:2 inclusion complexes could be observed. The average lifetime of the probe inside the CD cavity is larger than that observed in water due to hydrophobic and polarity effects of the nanocage. Anisotropy decay has been used to study the rotational dynamics of the molecule inside the cyclodextrin cavity. H-1 NMR data also confirm shallow inclusion of dapsone in beta-CD. PM3 semiempirical calculations indicate that for unimolar complex a partial (3.8 angstrom) encapsulation of the dapsone molecule in beta-CD at an angle of 72 degrees with the CD axis. The DFT calculations with solvent effect show that the formation of inclusion is spontaneous and enthalpy driven.