Abstract: In one aspect, compositions comprising emissive compounds including polycyclic aromatic groups are provided. In some embodiments, the emissive compounds may include various moieties having desirable physical and electronic properties. In some embodiments, the compositions may be useful for use in, for example, organic light-emitting diodes (OLEDs), chemical sensors, organic photovoltaics, and other devices. An advantageous feature of some embodiments described herein is the ability to tune the electronic properties of the compositions in order to suit a particular application. For example, compositions comprising emissive compounds described herein may exhibit thermally activated delayed fluorescence (TADF) and may be useful as emissive chromophores in e.g., OLED devices. In other cases, the compositions may exhibit high-lying triplet states and may be able to trap various triplet emitters, for use as e.g., host materials for OLED devices.