A range of molecules where the first excited singlet (S 1 ) and triplet (T 1 ) states violate Hund's rule have recently been discovered. Such compounds hold great promise as molecular emitters because the potentially emissive singlet state is thermodynamically favored over the non-emissive triplet, as illustrated in Figure . Inverted singlet-triplet gaps had been overlooked in a class of azaphenalenes, and were recently reexamined as emitters using coupled-cluster (CC)-based computational methods that can correctly predict Hund's rule violations. The inversion can occur in species where the overlap between the highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO) is minimal, which is the case in the highly symmetric azaphenalenes. Finally, Aizawa et al. confirmed the potential of the inverted gap mechanism experimentally in an OLED device. It is now imperative to realize the potential inverted gap emitter by establishing a rational design paradigm for promoting the inverted gap mechanism in molecules.