Inclusion complexation of 2-aminopyrimidines with β-cyclodextrin was studied in the solid state by infrared spectroscopy (IR), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The aminopyrimidine-β-CD complexes were also investigated in a solution by nuclear magnetic resonance spectral techniques (1H-NMR and 13C-NMR). Qualitative modifications in the position and number of peaks or bands obtained from spectral methods as well as thermal analysis indicated the inclusion.