“…Unfortunately, these PSs are often prepared via sophisticated molecular synthesis, require tedious organic purification, and show an inert response to external stimuli, which largely limit their high-throughput testing. Another strategy is the use of the supramolecular assembly to achieve improved PDT efficacy. − Compared with the single PS system, host–guest interactions have been recognized as an effective method to address dark cytotoxicity in vivo because the ROS generation and photophysical properties of PSs could be reversibly tuned by noncovalent molecular interactions, such as hydrophobic interactions, hydrogen bonding, coordinative bonds, and electrostatic interactions. , As an important component of host–guest architectures, regular-shaped organic macrocycles, such as calixarene, cyclodextrin, and cucurbituril, have been widely explored for their intrinsic cavities that can selectively bind guest molecules completely or partially. − Among them, calixarene is a well-known host motif and has emerged as an ideal skeleton for applications in drug delivery, biological imaging, and theranostic agents by virtue of its low toxicity and multiple response to stimuli. − For example, Guo and co-workers present a novel calixarene-based PDT system via biomarker-induced host–guest interactions …”