Abstract: An aromatic acridine derivative with photoremovable protecting group (PPG) properties was designed and synthesized. The host–guest recognition process between this guest molecule and cucurbit[n]uril (CB[n], n=7, 8, 10) was investigated, along with the effects of host–guest interaction on the photolysis of the guest in aqueous-phase using NMR, UV-Vis, and fluorescence spectroscopies. The results showed that CB[7] formed a 1:1 host–guest inclusion complex, while CB[8] formed both 1:1 and 1:2 complexes with the guest. Similarly, CB[10] exhibited a 1:2 binding mode. Furthermore, CB[7] was found to inhibit the photolysis, whereas CB[8] significantly enhanced the photolysis rate of the guest. This study highlights how subtle variations in CB[n] cavity size influence the photolysis reaction, offering insights into the design of CB[n]-based nanoreactor-mediated supramolecular systems for aqueous-phase photolysis of PPG molecules.

Key words: Photoremovable protecting group, Photolysis reaction, Host-guest interaction, Cucurbit[n]uril, nanoreactor