A modified bis-p-phenylene-34-crown-10 ring in which one disappearance of the 1,4-dioxybenzene type emission in the crown ether is due to a very efficient (k q Ն 4 ϫ 10 10 s Ϫ1 ) of the 1,4-dioxybenzene units has been replaced by a 9,10dioxyanthracene unit has been employed as a template for energy-transfer process from the 1,4-dioxybenzene to the 9,10-dioxyanthracene type unit. The absorption spectrum of the formation of cyclobis(paraquat-p-phenylene). The [2]catenane which results has been shown by 1 H NMR spectros-the [2]catenane is noticeably different from the sum of the spectra of its two cyclic components, particularly as far as the copy to exist in solution exclusively in the translationally isomeric form in which (a) only the 1,4-dioxybenzene ring occu-presence of a very broad charge-transfer (CT) band in the visible spectral region (λ max = 545 nm, ε max = 615 M Ϫ1 cm Ϫ1 ) pies the central cavity of the tetracationic cyclophane and (b) the crown ether ring is prevented from circumrotating is concerned. Comparison with the CT band of a model compound shows that the very broad CT band of the [2]catenane through the cyclophane by the large 9,10-dioxyanthracene unit. The absorption spectrum and luminescence properties is in fact the result of two component bands originating from the interaction of the two different electron-donor units (1,4-of this new [2]catenane and of its crown ether component in its free state have been investigated and compared with dioxybenzene and 9,10-dioxyanthracene type) present in the crown ether with the electron-acceptor bipyridinium-type those of 1,4-dimethoxybenzene and a model anthracene derivative, carrying methylated triethylene glycol chains on the units of the cyclobis(paraquat-p-phenylene). The emission spectrum of the [2]catenane does not show any band because 9 and 10 positions of the anthracene ring. While the absorption spectrum of the crown ether is the sum of the spectra of of the quenching action (rate constant k q Ն 5 ϫ 10 10 s Ϫ1 ) of the low-energy non-luminescent charge-transfer levels on the two component chromophoric moieties, its emission spectrum shows only the fluorescence band of the 9,10-dioxyan-the higher energy, potentially luminescent levels of the crown ether. thracene-type unit. The excitation spectrum shows that the