R(+)-alpha-lipoic acid (RALA) is a naturally-occurring substance, and its protein-bound form plays significant role in the energy metabolism in the mitochondria. RALA is vulnerable to a variety of physical stimuli, including heat and UV light, which prompted us to study the stability of its complexes with cyclodextrins (CDs). In this study, we have prepared and purified a crystalline RALA-CD complex and evaluated its properties in the solid state. The results of H-1 NMR and PXRD analyses indicated that the crystalline RALA-CD complex is a channel type complex with a molar ratio of 2:3 (RALA:-CD). Attenuated total reflection/Fourier transform infrared analysis of the complex showed the shift of the C=O stretching vibration of RALA due to the formation of the RALA-CD complex. Raman spectroscopic analysis revealed the significant weakness of the S-S and C-S stretching vibrations of RALA in the RALA-CD complex implying that the dithiolane ring of RALA is almost enclosed in glucose ring of -CD. Extent of this effect was dependent on the direction of the excitation laser to the hexagonal morphology of the crystal. Solid-state NMR analysis allowed for the chemical shift of the C=O peak to be precisely determined. These results suggested that RALA was positioned in the -CD cavity with its 1,2-dithiolane ring orientated perpendicular to the plane of the alpha-CD ring.