The synthesis of Cz-C-PTZSO 2 , Cz-CO-PTZSO 2 , Cz-C-TRZ and Cz-CO-TRZ is outlined in Scheme S1. All samples were purified by repeated silica column chromatography followed by temperature-gradient vacuum sublimation, and finally recrystallization from toluene. The molecular structures and purity were validated by a combination of 1 H & 13 C nuclear magnetic resonance spectroscopy (NMR), high-resolution mass spectrometry (HRMS), melting point determination, elemental analysis (EA), and high-performance liquid chromatography (HPLC) (Figures ).