Two novel evaporation- and solution-process-feasible thermally activated delayed fluorescence emitters, greenlight-emission ACRDSO2 and yellowlight- emission PXZDSO2, based on a brand-new electron-acceptor moiety thianthrene-9,9', 10,10'-tetraoxide, are developed for organic light-emitting diodes. The solution-processed devices, without any hole-transport layer, exhibit competitive performance and reduced efficiency roll-off compared with corresponding vacuum-deposited devices.