Coassembled Ionic\nOrganic Microcrystals with Bright\nCircularly Polarized Luminescence

The in situ protonation and crystallization of pyridine-functionalized\nsmall molecules <b>1</b>–<b>3</b> with enantiopure\ncamphor sulfonic acid afford ionic organic crystals, which exhibit\nbright blue circularly polarized luminescence (CPL) with high emission\nquantum efficiencies (Φ: 79–91%) and luminescence dissymmetry\nfactors in the 10<sup>–2</sup> order. These crystals are investigated\nby microscopy, absorption and emission spectral, and powder and single-crystal\nX-ray diffraction analyses. The chiral optical properties of these\nmicrocrystals are examined by circular dichroism and CPL studies.\nBy tuning the substitution position of the pyridine groups, microcrystals\nwith different morphologies and opposite CPL signals are achieved.