A bicyclooxacalixarene cage with triangular prism structure was synthesized by a one-pot SNAr reaction. The structure of the oxacalixarene cage 1 was characterized by NMR, MS spectra, and X-ray crystal structure analyses. In the solid state, the molecular cage was assembled into an interlaced porous network structure. Gas adsorption studies indicated that cage 1 exhibited high CO2/N2 selectivity of 106.