Synthesis, X-ray crystal structure and optical properties research of novel diphenyl sulfone-based bis-pyrazoline derivatives

► A series of novel diphenyl sulfone-based bis-pyrazoline derivatives were designed and synthesized. ► Their UV-vis absorption and fluorescence emission spectra were investigated. ► The relationship of substituents and the optical properties were discussed. ► With increasing the solvent polarity, fluorescence emission displayed a red-shift and fluorescence quantum yields decreased. ► Fluorescence was quenched when the concentration increased over to 10−5 M.