To investigate quantitatively the cooperative binding ability of β-cyclodextrin dimers, a series ofbridged bis(β-cyclodextrin)s with 2,2'-diselenobis(benzoyl) spacer connected by different lengths of oligo(ethylenediamine)s (2-5) and their platinum(Ⅳ) complexes (6-9) have been synthesized and their inclusion complexation behavior with selected substrates, such as Acridine Red, Neutral Red, Brilliant Green, Rhodamine B, ammonium 8-anilino-1-naphthalenesulfonate, and 6-p-toluidino-2-naphthalenesulfonic acid, were investigated by means of ultraviolet, fluorescence, fluorescence lifetime, circular dichroism, and 2D-NMR spectroscopy. The spectral titrations have been performed in aqueous phosphate buffer solution (pH 7.20) at 25°C to give the complex stability constants (KS) and Gibbs free energy changes (-△G°) for the inclusion complexation of hosts 2-9 with organic dyes and other thermodynamic parameters (△H°and T△S°) for the inclusion complexation of 2-5 with fluorescent dyes ANS and TNS. The results obtained indicate that β-cyclodextrin dimers 2-5 can coordinate with one or two platinum(Ⅳ) ions to form 1:1 or 1:2 stoichiometry metallobridged bis(β-cyclodextrin)s. As compared with parent β-cyclodextrin (1) and bis(β-cyclodextrin)s 2-5, metallobridged bis(β-cyclodextrin)s 6-9 can further switch the original molecular binding ability through the coordinating metal to orientate two β-cyclodextrin cavities and an additional binding site upon the inclusion complexation with model substrates, giving the enhanced binding constants KS for both ANS and TNS. The tether length between two cyclodextrin units plays a crucial role in the molecular recognition with guest dyes. The binding constants for TNS decrease linearly with an increase in the tether length of dimeric β-cyclodextrins. The Gibbs free energy change (-△G°) for the unit increment per ethylene is 0.32kJ•mol-1 for TNS. Thermodynamically, the higher complex stabilities of both ANS and TNS upon the inclusion complexation with 2-5 are mainly contributed to the favorable enthalpic gain (-△H°) by the cooperative binding of one guest molecule in the closely located two β-cyclodextrin cavities as compared with parent β-cyclodextrin. The molecular binding ability and selectivity of organic dyes by hosts 1-9 are discussed from the viewpoints of the multiple recognition mechanism and the size/shape-fitting relationship between host and guest.