Figure 2. Multimodal H-Bonds induced multiple optical behaviors in crystals. (A) Isomerization of HBT-DPI betweenOH-BS (black) and OH-DPI (purple). Fluorescence spectra of the crystal obtained in (B) TCM (HBT-DPI-N ), (C) DCM (HBT-DPI-Y ), (D) THF (HBT-DPI-G ), (E) EtOH (HBT-DPI-O ), λex = 365nm, slit: 5 nm/5 nm, inset: crystal pictures (top right-hand corner) and fluorescence photographs (bottom right-hand corner), TCM: chloroform, DCM: dichloromethane, THF: tetrahydrofuran, EtOH: alcohol. Crystal structures and intra-/intermolecular H-bonds of (F) HBT-DPI-N , (G)HBT-DPI-Y , (H) HBT-DPI-G , (I) HBT-DPI-Ocomposed by OH-BS (black) and OH-DPI (purple). (J) Table of the wavelength, molecular states, H-bonds and absolute fluorescence quantum yields of crystals. (K) The fluorescence spectra ofHBT-DPI-G , HBT-DPI-Y , and HBT-DPI-O tagged on a CIE 1931 chromaticity diagram.