The adsorption of toluene inside zeolite Na–Y was investigated by solid-state NMR spectroscopy. The environment of Na + ions at different sites in Na–Y before and after adsorption was characterized by 23 Na magic-angle spinning (MAS) NMR. The information on the dynamic behavior of guest molecules inside the supercage of Na–Y was obtained by analyzing wideline 2 H NMR spectra. The effect of loading level and temperature on molecular dynamics was also examined. The cation–sorbate interactions were directly probed by 23 Na{ 1 H} rotational-echo double-resonance (REDOR) experiments at different temperatures. Molecular Monte Carlo simulations were also performed to assist in the interpretation of the NMR data. 23 Na MAS and 23 Na{ 1 H} REDOR results show that each toluene molecule is facially coordinated to a Na + ion at the SII site in the supercage, forming a π-complex. The adsorption also causes the Na + ions initially located at the SI′ site to slightly shift to a new position within the sodalite cage, but has little effect on the Na + at the SI site. The 2 H NMR results indicate that the toluene molecules undergo a 2-site flip around the molecular long axis in addition to the methyl group rotation about its C 3 axis. 23 Na MAS spectra suggest that the adsorptive behavior of benzene and p-xylene in Na–Y is similar to that of toluene/Na–Y. 23 Na{ 1 H} REDOR results further indicate that inside the supercage, the degree of molecular motion follows the order of benzene>toluene>p-xylene.