NMR diffusion measurements provide unequivocal proof that the resorcinarene 1b self-assembles spontaneously into a stable hexamer capsule in chloroform solution by encapsulating several chloroform molecules, which occupy different chemical positions. Although the affinity of tetrahexylammonium bromide (2a) toward the cavity of the hexamer is much higher than that of the chloroform molecules, it was found that the same amount of DMSO is needed to disrupt the two hexamers, thus suggesting similar stabilities for these two supramolecular capsules.