Chemosensors detect a single target molecule from among several molecules, but cannot differentiate targets from one another. In this study, we report a molecular decoding strategy in which a single host domain accommodates a class of molecules and distinguishes between them with a corresponding readout. We synthesized the decoding host by embedding naphthalenediimide into the scaffold of an entangled porous framework that exhibited structural dynamics due to the dislocation of two chemically non-interconnected frameworks. An intense turn-on emission was observed on incorporation of a class of aromatic compounds, and the resulting luminescent colour was dependent on the chemical substituent of the aromatic guest. This unprecedented chemoresponsive, multicolour luminescence originates from an enhanced naphthalenediimide-aromatic guest interaction because of the induced-fit structural transformation of the entangled framework. We demonstrate that the cooperative structural transition in mesoscopic crystal domains results in a nonlinear sensor response to the guest concentration.

This minireview is devoted to honoring the memory of Dr. Thomas Dougherty, a pioneer of modern photodynamic therapy (PDT). It compiles the most important inputs made by our research group since 2012 in the development of new photosensitizers based on BODIPY chromophore which, thanks to the rich BODIPY chemistry, allows a finely tuned design of the photophysical properties of this family of dyes to serve as efficient photosensitizers for the generation of singlet oxygen. These two factors, photophysical tuning and workable chemistry, have turned BODIPY chromophore as one of the most promising dyes for the development of improved photosensitizers for PDT. In this line, this minireview is mainly related to the establishment of chemical methods and structural designs for enabling efficient singlet oxygen generation in BODIPYs. The approaches include the incorporation of heavy atoms, such as halogens (iodine or bromine) in different number and positions on the BODIPY scaffold, and also transition metal atoms, by their complexation with Ir(III) center, for instance. On the other hand, low‐toxicity approaches, without involving heavy metals, have been developed by preparing several orthogonal BODIPY dimers with different substitution patterns. The advantages and drawbacks of all these diverse molecular designs based on BODIPY structural framework are described.

The molecular structure and the photophysical properties of pyrromethene-BF₂ (PM) dyes are studied with the aim of finding the best structural and environmental conditions which optimize the laser performance of these dyes. To this end, UV–Vis absorption and fluorescence spectra and fluorescence decay curves of several PM dyes are registered in a multitude of solvents with different physicochemical properties and in polymeric solid matrices. Quantum mechanical calculations at different levels are also applied in order to explain the photophysical behaviour of these dyes. The studied pyrromethenes incorporate alkyl (methyl, ethyl and tert-butyl), sulfonate, cyano, and acetoxy- and methacryloyloxy-polymethylene groups in different positions of the chromophore. In the last case, the presence of the polymerizable acryloyl group facilitates the covalent linkage of the chromophore to a polymeric chain, of special technological interest in the development of tunable dye lasers in the solid state. From the experimental results and the theoretical calculations, we discuss different mechanisms of internal conversion for PM dyes, such as the loss in the planarity of the chromophore, the electron flow through the delocalized π-system, the vibrational coupling and the formation of an intramolecular charge transfer state. The present work demonstrates the good correlation between the photophysical and the lasing properties of PM dyes with different structural (substituents) and environmental (solvents and polymers) conditions.