LAUSR

In this chapter, we demonstrated different strategies toward the construction of photochromic crown ethers in order to obtain the capability to recognize the chemical guest while retaining the photoswitchability. The complex formation in photochromic crown ether can be either spontaneous or stimulated by irradiation with light of the photochromic part. In the same way, light can disrupt the metal cation—crown ether interaction. Thus, the photochromic crown ethers demonstrate a new level of molecular sensing when receptor can bind reversibly so that they can overcome the problem of one-time sensor. Photochromic crown ethers can be a suitable platform to obtain multitask sensors and photo-switchable supramolecular systems.