Tetraphenylethylene‐Interweaving Conjugated Macrocycle Polymer Materials as Two‐Photon Fluorescence Sensors for Metal Ions and Organic Molecules

A luminescent conjugated macrocycle polymer (CMP) with strong two‐photon fluorescence property, namely, P5]‐TPE‐CMP, is constructed from ditriflate‐functionalized pillar5]arene and a 1,1,2,2‐tetrakis(4‐ethynylphenyl)ethylene (TPE) linker through a Sonogashira–Hagihara cross‐coupling reaction. Significantly, in sharp contrast with the corresponding conjugated microporous polymer without synthetic macrocycles, P5]‐TPE‐CMP shows an outstanding stability against photobleaching and exhibits highly selective cation sensing capability toward Fe³⁺ at different excitation wavelengths (both UV and red–near‐infrared regions). Meanwhile, its fluorescence could also be sufficiently quenched by 4‐amino azobenzene, a frequently used organic dye that is certified to be carcinogenic, as compared with a group of common organic compounds. This work paves a new way for enhancing the properties of porous organic polymers through the introduction of supramolecular macrocycles like macrocyclic arenes.