Herein, we demonstrate an easy-to-access synthetic route to construct a boron, nitrogen, and oxygen doped ladder type nonacene. The emitter NOBNacene is the first example of a π-extended MR-TADF emitter that has nine, six-membered rings fused along one dimension. Strikingly, this π-extended design shows only a limited conjugation length, reflected in emission in the deep blue region in THF solution (lPL = 405 nm, FWHM = 40 nm, FPL = 33%) and in the 1.5 wt% TSPO1 film (lPL = 410 nm, FWHM = 38 nm, FPL = 71%, td = 1.77 ms). This design utilizes two electronically distinct boron acceptor atoms and a combination of nitrogen and oxygen donor atoms. Deep blue EL (λEL= 409 nm, FWHM = 37 nm) was produced when NOBNacene was employed as the emitter in the OLED. An EQEmax of 8.5%