We describe the synthesis of a boxlike cyclophane 1, its complexation with p-nitrophenol, the temperature dependence of the H-1 NMR spectra of the 1:p-nitrophenol complex, and the effect of solvent on complexation. Cyclophane 1 was designed to test our previous observations on the effect of cavity size and pi-hydrogen bonds in stabilizing host-guest complexes in nonpolar solvents. It exhibits an association constant with p-nitrophenol in excess of 400 000 M-1 in CDCl3. The high stability of the complex is paralleled by slow exchange between free and complexed cyclophane. The axial spinning of the xylene units of the host is slow in the complex but fast in the free host. It is shown that the rate-determining step for xylene spinning is dissociation of the complex. The two guest protons ortho to the nitro group in the phenol are distinct in the complex; their interconversion requires its dissociation. Both K(assoc) and k(exch) are dependent on the solvent. Solvents that are "big" (chloroform and tetrachloroethane) exhibit large K(assoc) values and slow exchange, while small" solvents (dichloromethane and 1,2-dichloroethane) exhibit both smaller K(assoc) values and faster exchange. These solvent effects are interpreted in terms of a binding model involving displacement of one intracavity species by another.