Nanoporous materials are important in applications such as molecular separations, catalysts and gas storage. Metal-organic frameworks (MOFs), covalent organic frameworks (COFs), and nanoporous polymers have dominated this research area. By contrast, discrete organic molecules tend to pack efficiently in solid state, leaving as little empty space as possible, which leads to non-porous materials. This review will highlight the recent developments with discrete organic cage molecules that are porous in solid state.