A series of bridged β-cyclo- dextrin(β-CyD) dimers possessing functional tethers of various lengths was synthesized in moderate yield by the treatment of 2,2’-biquinoline- 4,4’-dicarboxylic dichloride with β-CyD or mono[6-oligo(ethylenediamino)-6- deoxy]-β-CyDs. The products were 2,2’-biquinoline-4,4’-dicarboxy-bridged bis(6-O-β-CyD)(8), N,N’-bis(2-amino- ethyl)-2,2’-biquinoline-4,4’-dicarbox- amide-bridged bis(6-amino-6-deoxy-β- CyD)(9), and N,N’-bis(5-amino-3-aza- pentyl)-2,2’-biquinoline-4,4’-dicarbox- amide-bridged bis(6-amino-6-deoxy-β- CyD)(10). The reaction of 8-10 with copper perchlorate give their copper(II) complexes 11-13 in satisfactory yields of over 77%. All the bis(β-CyD)s 8-13 act as efficient fluorescent sensors and display remarkable fluorescence enhancement upon addition of optically inert steroids. The inclusion complexa- tion behaviors of 8-13 when treated with the representative steroids cholate(14), deoxycholate(15), and glycocho- late(16) in aqueous solution at 25℃ were investigated by means of UV/Vis spectroscopy, conductivity and fluorescence measurements, circular dichroism spectroscopy, and 2D NMR spectroscopy. The tether length of bis(β-CyD) 9 allows it to adopt a cooperative host-tether-guest binding mode in which the spacer and guest are co-included in the two CyD cavities. As a result of this cooperation, 9 has a stability constant[Ks] about 2×102 times higher than that of monomodified β-CyD 4 for inclusion complexation with cholate. Metallooligo(β-CyD)s with four β- CyD units have enhanced binding abilities compared with monomodified β-CyDs. These metallo compounds have binding affinities for guest steroids that are up to 50-4.1 ×103 times higher than those of CyDs 2-4. The guest-induced fluorescence enhancement of bis(CyD)s opens a new channel for the design of sensor materials. The complex stability constants of these compounds are discussed from the viewpoint of induced-fit interaction and cooperative multiple binding between host and guest.