Herein, we present a feasible strategy for fabricating photo/thermal-responsive size switchable supramolecular nanoparticles assembly based on the unprecedented host-guest inclusion complex between anionic pillararene 2C-WP5A and azobenzene derivation G in aqueous solution (Fig. 1). The design proposed here combines the following advantages: (1) the percarboxylatopillararenes is the most used anionic pillararene, which can be obtained easily and efficiently; (2) differing from the α-cyclodextrin, either trans- and cis- azobenzene derivatives G could be included in 2C-WP5A with similar affinity, which could result in the only reversible change of the nanoparticle’s size without disassembling; (3) the size change by photo/thermal-stimulation would result in the reversible switching the transparency of solution from turbid to clear.