A novel isobenzofuran-isocoumarin hybrid molecule obtained as an unexpected product: optimized synthesis, structural and photophysical characterization, and theoretical analysis

Abstract This study reports the synthesis, structural elucidation, and optical characterization of a novel hybrid molecule integrating isobenzofuran and isocoumarin frameworks namely 3-(2-(3-oxo-1,3-dihydroisobenzofuran-1-yl)acetyl)-1H-isochromen-1-one (IBF–IC). The compound was obtained as an unexpected product during the reinvestigation of a solvent-free reaction protocol originally developed for the synthesis of 3-acetylisocoumarin and was isolated in high yield after targeted optimization. Its molecular structure was confirmed by FTIR, 1 H NMR, and 13 C NMR spectroscopy, and its wavelength-dependent photophysical behavior was evaluated by UV–Vis spectroscopy. Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations were further employed to investigate the vibrational, electronic, and nonlinear optical characteristics of IBF-IC. The findings indicate that IBF-IC may have potential for use in optoelectronic devices. In addition, to the best of our knowledge, this work represents the first comprehensive experimental and theoretical investigation, highlighting IBF-IC as a promising candidate for nonlinear optical, optoelectronic, and photonic applications.