The location of benzene in KL zeolite upon coadsorption of ammonia and CH3NH2 has been investigated and the interaction strength of ammonia, methylamine, and benzene with KL has been evaluated by means of infrared spectroscopy. The adsorption behavior of benzene in KL zeolite has been correlated with the average negative charge of oxygen atoms, with the counterions, with the zeolite structure, and with the interaction strength of ammonia, methylamine, and benzene with KZ, zeolite. The ammonia and methylamine molecules can interact with Ri ions via the lone pair on nitrogen atoms and with the residual silanols present in dehydrated KZ, zeolite. The desorption experiments demonstrate that the interaction strengths of ammonia, methylamine, and benzene with KL rank in the following order: methylamine/KL > benzene/KL > ammonia/KL. It has been found that adsorption of methylamine, but not ammonia, causes the appearance of some broad features in the skeleton vibration range, indicating a modification of the lattice parameter: precisely, a deformation of the zeolite framework. It has also been observed that besides benzene adsorption on counterions, the 12R windows occurring in KL, which are not the preferential adsorption sites for benzene in the presence of benzene alone or upon coadsorption of ammonia, become favorable adsorption sites for benzene upon coadsorption of methylamine. The present work evidences once again the structural effect in adsorption of benzene. We think that the fact that the 12R windows become indeed adsorption sites for benzene upon coadsorption of methylamine should be related to the deformation of the zeolite framework, precisely the 12R windows. It is possible that the 12R windows in KL zeolite are initially not compatible with benzene molecules from the point of view of the structure but that the deformation gives a beneficial effect and the 12R windows become favorable for adsorption of benzene.