Crown ethers, discovered by the winner of the Nobel Prize Charles Pedersen, are cyclic chemical compounds that consist of a ring or multiple rings containing several ether groups that are capable of binding alkali ions. A smart fluorescent probe containing a crown ether moiety could be developed as a sensor for metal ions, anions and other bio-molecules and be further applied to monitor the relevant biological process in vivo. This review highlights recent advances which can be divided into seven parts: (i) fluorescent probes containing a simple crown ether or an aza-crown ether structure; (ii) fluorescent probes containing an azathia crown ether; (iii) fluorescent probes containing a cryptand; (iv) fluorescent probes containing two or more binding sites; (v) crown ether derivatives-metal complex assisted chemosensing of bioactive species; (vi) crown ether-based chemosensors for bioactive molecular detection; and (vii) efforts to improve biological relevance.

We developed a novel NIR-harvesting n-type porphyrin derivative, PDI–PZn–PDI, that shows a low bandgap of 1.27 eV. Panchromatic absorption was extended to the NIR area with a significantly low energy loss of 0.54 eV which led to promising photovoltaic performance.

While the outstanding charge transport and sunlightharvesting properties of porphyrin molecules are highly attractive as active materials for organic photovoltaic (OPV) devices, the development of ntype porphyrin-based electron acceptors has been challenging. In this work, we developed a high-performance porphyrin-based electron acceptor for OPVs by substitution of four naphthalene diimide (NDI) units at the perimeter of a Zn-porphyrin (P Zn ) core using ethyne linkage. Effective πconjugation between four NDI wings and the P Zn core significantly broadened Q-band absorption to the near infrared region, thereby achieving the narrow band gap of 1.33 eV. Employing a windmill-structured tetra-NDI substituted P Zn -based acceptor (P Zn -TNDI) and mid-band gap polymer donor (PTB7-Th), the bulk heterojunction OPV devices achieved a power conversion efficiency (PCE) of 8.15% with an energy loss of 0.61 eV. The PCE of our P Zn -TNDI-based device was the highest among the reported OPVs using porphyrin-based acceptors. Notably, the amorphous characteristic of P Zn -TNDI enabled optimization of the device performance without using any additive, which should make industrial fabrication simpler and cheaper.