Coumarins are a set of polyphenolic compounds isolated from plant product tonka bean, coumarou in 1820. They belong to the family of benzopyrones, which includes benzene ring joined with the aid of a pyrone ring. Coumarins have attracted great attention of medicinal chemists and pharmacologists in recent years as they been confirmed to bear diverse pharmacological activities like antiinflammatory and analgesic, anti oxidant, anticancer, etc. This review highlights the method of preparation, chemical reactivity, and organic properties such as anti-inflammatory, anticoagulant, antioxidant, anticancer and analgesic activities, of coumarins and their analogues.

Organic–inorganic lead halide perovskites materials have emerged as an innovative candidate in the development of optoelectronic and photovoltaic devices, due to their appealing electrical and optical properties. Herein, mix halide single-layer (~95 nm) and multilayer (average layer ~87 nm) CH₃NH₃PbIBr₂ thinfilms were grown by a one-step spin coating method. In this study, both films maintained their perovskite structure along with the appearance of a pseudo-cubic phase of (200) at 30.16°. Single-layer and multilayer CH₃NH₃PbIBr₂ thinfilms displayed leaky ferroelectric behavior, and multilayered thinfilm showed a leakage current of ~5.06 × 10⁻⁶ A and resistivity of ~1.60 × 10⁶ Ω.cm for the applied electric field of 50 kV/cm. However, optical analysis revealed that the absorption peak of multilayered perovskite is sharper than a single layer in the visible region rather than infrared (IR) and near-infrared region (NIR). The band gap of the thinfilms was measured by Tauc plot, giving the values of 2.07 eV and 1.81 eV for single-layer and multilayer thinfilms, respectively. The structural analysis has also been performed by Fourier transform infrared spectroscopy (FTIR). Moreover, the fabricated CH₃NH₃PbIBr₂ as an absorber layer for photoelectric cell demonstrated a power conversion efficiency of 7.87% and fill factor of 72%. Reported electrical, optical and photoelectric efficiency-based results suggest that engineered samples are suitable candidates for utilization in optoelectronic and photovoltaic devices.