Herein, we present two new isomeric p-extended C=O/N-based polycyclic aromatic compounds based on the annellation of two triangulene DiKTa units to form tetraketone structures. Differently from QA-2 and Hel-DiDiKTa, the central ring in each of Sym-DiDiKTa and Asym-DiDiKTa is functionalized with para-C=O-π-C=O and N-π-N groups, these molecules represent the first ketone-based MR-TADF examples of their kind (Figure ). Sym-DiDiKTa is composed of nine fully fused rings with symmetrically arranged tert-butyl substituents while the tert-butyl groups are disposed asymmetrically in Asym-DiDiKTa. Both emitters show moderate DEST of around 0.23 eV, red-shifted emission at ~540 nm compared to DiKTa, a small FWHM of 29 nm and delayed lifetime, τd, of 1700 µs and 2100 µs for Sym-DiDiKTa and Asym-DiDiKTa, respectively.