Siloles symmetrically substituted on their 2,5-positions with electron-accepting and donating moieties: facile synthesis, aggregation-enhanced emission, solvatochromism, and device applicationElectronic supplementary information (ESI) available: Characterization data (Fig. S1S9), DSC graphs (Fig. S10), PL and UV spectra of silole derivatives (Fig. S11S13), photo images of silole derivatives (Fig. S14), detailed crystal structure analysis (Fig. S15S17), normalized absorption spectra of silole der

Three dimethyltetraphenylsiloles (DMTPSs) symmetrically substituted on their 2,5-positions with electron-accepting (A), i.e. aldehyde (ALD) and dicyanovinyl (DCV) or donating (D), i.e. diphenylamine (DPA) moieties were designed and synthesized via facile reaction procedures. The propeller-shaped luminogens exhibit aggregation-induced/enhanced emission characteristics with high quantum yields up to 74.0% in the solid state, and are thermally stable, showing high degradation temperatures and melting points up to 388 and 246 C, respectively. Thanks to the contained A or D moieties, the siloles show intriguing solvatochromism: DMTPS-ALD exhibits almost no response to solvents due to the balance of electron affinities of the aldehyde and the silole core. Whereas, DMTPS-DCV and DMTPS-DPA possess outward intramolecular charge-transfer (ICT) from the silole core and the phenyl rings on its 3,4-positions to dicyanovinyl groups, and inward ICT from diphenylamine groups to the silole core, respectively, showing positive solvatochromism. A multilayer organic light-emitting diode using DMTPS-DPA among the luminogens as an emitter layer shows the highest performance with turn-on voltage, maximum luminance, current, power, and external efficiencies of 3.1 V, 13405 cd m 2 , 8.28 cd A 1 , 7.88 lm W 1 , and 2.42%, respectively. Furthermore, DMTPS-DPA can also serve in hole-transporting layers because of its high hole-mobility. Therefore, the incorporation of a triphenylamine moiety into a silole system not only changes the classical aggregation-caused quenching fluorophore into AEE-active DMTPS-DPA, another example of turning stone into gold, but also enhances the hole-transporting ability of siloles. Symmetrically substituted siloles with polar groups on their 2,5-positions exhibit unique aggregation-induced/enhanced emission, solvatochromism effect, and intriguing intramolecular charge-transfer (ICT).