Despite the recent advancements in deciphering the underpinning rules of flexibility in organic single crystals and their superior device performance due to the nearly defect-free packing, flexible organic single crystals are scarcely used in electronic devices. Single crystals that can produce multiple readouts in response to different external stimuli could be immensely useful for molecular logic operations. Here, we report the modulation in the mechanical flexibility and fluorescence of the single crystals of a pyrene-functionalized naphthalidenimine in response to multiple chemical stimuli. Crystallographic investigations revealed that subtle changes in the weak intermolecular interactions play a critical role in defining the mechanical flexibility of these crystals. Furthermore, the multistimuli responsive mechanical and luminescence properties of these single crystals were utilized for building a multiple-input, multiple-output molecular logic gate.

Boron-containing organic compounds are well accepted as a class of compounds having excellent photophysical properties. In addition to the unique photophysical properties, the ease of synthesis and structural robustness make tetracoordinate boron complexes ideal for a variety of applications. While significant light has been thrown on their luminescence properties, there is no collective attention to their supramolecular chemistry. In this mini review, we discuss the progress made in the supramolecular chemistry of these compounds which includes their utility as building blocks for liquid crystalline materials and gels largely driven by various non-covalent interactions like H-bonding, CH-π interactions, BF-π interactions and Van der Waals forces. The organoboron compounds presented here are prepared from easy-to-synthesize chelating units such as imines, diiminates, ketoiminates and diketonates. Moreover, the presence of heteroatoms such as nitrogen, oxygen and sulfur, and the presence of aromatic rings facilitate non-covalent interactions which not only favor their formation but also helps to stabilize the self-assembled structures.

Fluoride ions are indispensable in biology and environmental science and hence the selective and sensitive detection of fluoride is important. This work reports the design and synthesis of a tripodal Schiff's base 1 through a simple condensation reaction between a commercially available aldehyde and an amine. Single crystal X‐ray crystallography revealed that compound 1 is a planar entity with the three salicylidene derivatives on the three arms of the central phenyl moiety linked by imine groups. Compound 1 forms a molecular dimer that resembles a six‐petal flower and is stabilized through multiple intermolecular interactions such as C−H.π and π.π interactions. Compound 1 exhibited moderately good emission in the solid state with aggregation induced emission and reversible mechanofluorochromic properties. Moreover, 1 was observed to selectively detect fluoride among various anions with a limit of detection of ∼9 ppm. Compound 1 was also capable of detecting fluoride under a variety of conditions such as in thin films and under cellular conditions.

Development of chemosensors for metal ions is an active area of research. Fluorescent chemosensors capable of detecting multiple metal ions are valuable because of their potential utility in diagnostics and environmental science. We have synthesized a Schiff‐base chemosensor based on the tetraphenylethylene chromophore. It was observed that the chemosensor interacts with Cu(II) and Zn(II) in acetonitrile with high association constants of 2.33 × 1021 and 1.33 × 1021 M−4, respectively. Moreover, the interaction of these metal ions with the chemosensor resulted in visual colour and fluorescence changes. Nanoaggregates of this molecule, on the other hand, were observed to be selective towards Cu(II) in the aqueous medium. It is also noteworthy that the binding of Cu(II) activates photosensitization property of this molecule and generates singlet oxygen efficiently.