The diffuse reflectance UV-visible absorption and Raman scattering spectrometry provide evidence of sorption of 2,2'-bipyridine (bpy, C10H8N2) as intact molecules into nonacidic MFI zeolites, silicalite-1, and Al-ZSM-5. The effect of the aluminum content n, the nature of the charge-balancing cation Mn+ as well as bpy loading in M-m/n(AlO2)(m)(SiO2)(96-m) (M(m/n)ZSM-5; m = 0, 3, 6; n =1, 2; M = Na+, Zn2+) were examined. The Raman scattering as well as the X-ray powder diffraction experiments provide evidence of weak structural deformations of hosts upon bpy sorption. Clear evidence has emerged from Raman and UV-visible spectroscopic experiments to support the contention that sorption of bpy in dehydrated MFI type zeolites results in three different bpy conformations according to the aluminum content of the framework and the nature of extraframework cations. The modeling investigations using Monte Carlo simulations, molecular mechanics, and molecular dynamics calculations provide coherent structural support to the interpretation of spectroscopic results. It appears that the size and shape of straight channel itself of MFI type zeolites does not generate energetic and steric constraints to change the trans planar structure of free bpy molecule. Thus, the sorption of 2,2'-bipyridine into purely siliceous silicalite-l retains the trans-planar conformation. The nonbonding interactions between the extraframework Na+ cation and occluded bpy in Na(n)ZSM-5 are the main driving forces that stabilize the cisoid nonplanar conformer, whereas the coordination bonding between Zn2+ and N atoms in Zn(3)ZSM-5 requires the cis-planar conformation. The spectroscopic and modeling results were found to be in agreement with previous quantum calculations concerning the conformational behavior of free 2,2'-bipyridine relative to the inter-ring rotation.