Semiempirical PM3 and density function theory B3LYP/3-21g* calculations in vacuum and in water indicated that the “syn” orientation was preferred in the 1:2 complex of cucurbit[8]uril with protonated 2, 6-bis(4, 5-dihydro-1H-imidazol-2-yl)naphthalene. The (-( stacking interaction between the two substrate molecules was proposed as the physical origin of such a behavior. Semiempirical PM3 and density function theory B3LYP / 3-21g * calculations in vacuum and in water indicates that the “syn” orientation was preferred in the 1: 2 complex of cucurbit [8] uril with protonated 2, 6-bis (- stacking interaction between the two substrate molecules was proposed as the physical origin of such a behavior.