Pratima Surati
Abstract Schiff base pyrazolone derivatives have attracted considerable interest owing to their remarkable photochromic and electrochromic properties, which make them promising candidates for molecular switches, sensors, and advanced optical materials. In this study, Schiff base 4-[1-(1,5-dimethyl-3-oxo-2-phenyl-pyrazolidin-4-ylimino)-ethyl]-5-methyl-2-phenyl-2,4-dihydro-pyrazol-3-one (A) was successfully synthesized and structurally characterized by NMR, IR, LC-MS, and UV–vis absorption spectroscopy. The compound exhibited distinct photochromic and electrochromic responses upon external optical and electrical stimulation. The observed photochromic behavior is attributed to a reversible photoinduced enol–keto transformation within the pyrazolone framework.