When azobenzene moieties are incorporated into a macrocycle, a shape change of the macrocycle can be stimulated reversibly by irradiation with light. If carefully designed, the macrocycle can have a more “open” and more “closed” state, analogous to a molecular gate or iris. As is often observed in discotic liquid-crystalline phases, self-assembly of shape-persistent macrocycles can result in the macrocycles stacking one on top of the other to form columns. By this rationale, a fluid nanoporous network with photo-modulated pore sizes could be realized. Based on this motif, we have designed and synthesized a photoresponsive macrocyclic liquid crystal. Significant conversion of the macrocycles from the more closed state into the more open state can be achieved both in Langmuir monolayers, and in the bulk columnar liquid-crystalline condensed states.