As a new class of macromolecules, pillar[n]arenes (5–15) have been extensively studied from their synthesis, functionalization and supramolecular chemistry since 2008313233343536. The first photo-responsive host-guest complexation based on pillararene and azobenzene-guest was reported by Huang in 201237. Thereafter, the author constructed a dual-responsive supra-amphiphilic polypseudo-rotaxane based on pillararene and azobenzene derivative in aqueous solution38. Meanwhile, Ogoshi also reported a photoreversible switching of the lower critical solution temperature (LCST) in host-guest system of pillararene and azobenzene derivative39. Up to now, most reported photo-responsive systems based on azobenzene and pillar[n]arene are mainly focus on pillararene404142. Nevertheless, the diameter of the internal cavity of pillararene is ~4.7 Å, which is equal to α-cyclodextrin (~4.7 Å)43. In accordance with common sense, it is reasonable that the pillararene and azobenezene derivative could form host-guest inclusion complexation. Ogoshi has studied the threading process of pillararene onto a viologen derivative containing an azobenzene end-group44. But there has been no direct proof to reveal the host-guest complexation between anionic pillararene and photo-responsive azobenzene derivatives. Considering the easier access to pillararene compared with pillararene and the aforementioned reasons, it is necessary to investigate the host-guest complexation and assembly behavior based on pillararene and azobenzene derivatives. In addition, to the best of our knowledge, size switchable supramolecular nanoparticles formed by host-guest interactions between anion pillararene and azobenzene derivatives have been underexplored.