Phenothiazine (PTZ) is one of the most extensively investigated S, N heterocyclic aromatic hydrocarbons due to its unique optical, electronic properties, flexibility of functionalization, low cost, and commercial availability. Hence, PTZ and its derivative materials have been attractive in various optoelectronic applications in the last few years. In this prospective, we have focused on the most significant characteristics of PTZ and highlighted how the structural modifications such as different electron donors or acceptors, length of the π-conjugated system or spacers, polar or non-polar chains, and other functional groups influence the optoelectronic properties. This prospective provides a recent account of the advances in phenothiazine derivative materials as an active layer(s) for optoelectronic (viz. dye sensitized solar cells (DSSCs), perovskite solar cells (PSCs), organic solar cells (OSCs), organic light-emitting diodes (OLEDs), organic field-effect transistor (OFETs), chemosensing, nonlinear optical materials (NLOs), and supramolecular self-assembly applications. Finally, future prospects are discussed based on the structure–property relationship in PTZ-derivative materials. This overview will pave the way for researchers to design and develop new PTZ-functionalized structures and use them for various organic optoelectronic applications.

The splitting of water into hydrogen and oxygen under visible light is an emerging phenomenon in green energy technology. Nevertheless, selecting an appropriate photocatalyst is rather significant to enhance hydrogen production on a large scale. In this context, organic photocatalysts have received considerable attention owing to their larger surface area, control in diffusion adsorption, nanostructures and electronic properties. Herein, we have developed five either free base or transition metalated porphyrin–napthalimide based donor–acceptor systems (PN1–PN5) and studied their morphology, electronic properties and catalytic behaviour. Detailed studies suggest that the Co(II) substituent D–A system (PN2) displayed a well-aligned one-dimensional (1D) nanowire with high electrical conductivity promoting remarkable photocatalytic hydrogen production rate (18 mM g⁻¹ h⁻¹) when compared to that of porphyrin-based derivatives reported until now. Thus, these results propose to investigate diverse metalated π-conjugated materials as photocatalysts for hydrogen production.

The potential of using non-planar triphenylimidazole-donor-based dyes in dye-sensitized solar cells was explored via synthesizing two novel dyes, LG-P1 and LG-P3 , with D–D–π–A and D–A–π–A architectures, respectively.

Fluoride ion plays a pivotal role in a range of biological and chemical applications however excessive exposure can cause severe kidney and gastric problems. A simple and selective molecular sensor, 4,5-di(thien-2-yl)-2-(4-(1,2,2-triphenylvinyl)-phenyl)-1H-imidazole, DTITPE, has been synthesized for the detection of fluoride ions, with detection limits of 1.37 × 10⁻⁷ M and 2.67 × 10⁻¹³ M, determined by UV-vis. and fluorescence spectroscopy, respectively. The variation in the optical properties of the molecular sensor in the presence of fluoride ions was explained by an intermolecular charge transfer (ICT) process between the bis(thienyl) and tetraphenylethylene (TPE) moieties upon the formation of a N-H---F⁻ hydrogen bond of the imidazole proton. The sensing mechanism exhibited by DTITPE for fluoride ions was confirmed by ¹H NMR spectroscopic studies and density functional theory (DFT) calculations. Test strips coated with the molecular sensor can detect fluoride ions in THF, undergoing a color change from white to yellow, which can be observed with the naked eye, showcasing their potential real-world application.