Charge-transfer (CT) complexes of 1,2,4,5-tetracyanobenzene (TCNB) with arene donor molecules were assembled within the supercages of faujasite zeolites with a two-step adsorption technique from solutions, and the transient absorption characteristics as well as the absorption and emission properties of these complexes were investigated. Several observations were made relevant to these neutral-type CT complexes which are adsorbed with a weak electronic interaction into zeolites rather than the Coulombic attraction which is predominant for the binding of CT complexes of pyridinium accepters previously studied: (1) the peak position of the CT bands suffers an appreciable shift depending on the chemical nature of the zeolites, (2) the apparent equilibrium constant for the complex formation depends both on the chemical nature of the zeolites and on the arene donors, (3) an appreciable effect of coadsorbed water, which has stronger interaction with the zeolite frameworks than the guest species, on the complex formation is noted, and (4) the relaxation process of the excited CT complexes is significantly retarded (at least 10 times) in dehydrated zeolites compared with that in polar solutions. These points were discussed on a qualitative basis because of the complexity of the systems. The CT complexes of TCNB with arene donors were found to be sensitive to the chemical properties of zeolites while those of pyridinium accepters with arenes have been reported to be sensitive to the physical properties such as the shape of cages as well as the size of entry apertures of zeolites.