Organic semiconductors have shown to be able to replace their inorganic counterparts in almost every optoelectronic device, namely transistors, solar-cells, and light-emitting diodes (LEDs). Organic semiconductors have significantly contributed to the simplification of the respective device architecture as well as their fabrication, with performances that rival those of inorganic semiconductors. The versatility of organic semiconductors has led to a variety of special features like biocompatibility and degradability, as well as semi-transparent and flexible devicesproperties that are typically unattainable in devices made from inorganic semiconductors. Extensive research has produced numerous organic laser gain media covering almost the entire visible spectrum. Such organic semiconductors exhibit substantial gain and would therefore present ideal materials for lasers. In fact, high performance organic LEDs (OLEDs) are sufficiently bright to optically pump an organic laser gain medium. Despite this electrically driven but optically pumped all-organic laser diode, a direct electrically pumped organic laser is still not available to date. This limitation stems from two inherent properties of organic semiconductors: their low charge carrier mobility and their spin-statistical limit, where only one emissive singlet exciton is produced in four injected electrons. The remaining three excitons are created as dark and relatively long-lived triplet states. In a laser device, where the emissive states are harvested by stimulated emission, triplet states pile up over time, eventually hindering efficient population inversion. In addition, the low charge carrier mobility of organic semiconductors requires fabrication of very thin emissive layers to prevent quenching of the produced excitons by polarons; however, in thin film devices, the electrodes for charge injection are close to the gain material, leading to absorption of the laser mode that should be amplified. Since spin-statistics also limit the efficiency of OLEDs, several approaches have been pursued to convert once produced triplet excitons into emissive singlets. One strategy is to use thermally activated reverse intersystem crossing (RISC) to convert triplets into emissive singlets. However, the fluorescence from the triplets converted to singlet states is significantly delayed and, while being useful in OLEDs, these materials cannot overcome the problems associated with electrically pumped lasers. In the meantime, several other mechanisms have emerged, where the conversion does not require thermal activation and the delayed fluorescence has decay rates that are only marginally different from the prompt emission. Emitter materials, in which such upperlevel RISC is possible, are typically based on acenes. Acenes, are known to exhibit low lying T1 triplet states at approximately half the energy of the singlet gap, leading to higher excited triplet states ≥ T2 that are in close energetic proximity and aligned with the first excited singlet state S1. Functionalized anthracene, pyrazine, and various boron-containing compounds have shown to make use of these states, allowing the combination of fast RISC and amplified spontaneous emission (ASE). Pyrenes have similar electronic configuration but also exhibit exceptionally high fluorescence quantum yields ϕ. For example, a pyrene multi-substituted with diphenylamine fluorene shows ϕ as high as 95%. The optical properties, like absorption and emission wavelengths, can be tailored by varying the substituents and their positions on the pyrene core. Because of these beneficial properties, there are several substituted pyrene compounds reported, which exhibit ASE or even laser emission. Most of these are fourfold substituted pyrene cored starburst molecules. The ASE threshold represents the minimum required pump energy density to reach population inversion. In such pyrene materials, these ASE thresholds are as low as 1.75 and 20.5 µJ cm -2 , with sharp emission bands between 479 nm and 530 nm for the tetra-substituted materials, while the emission wavelength can be reduced to 475 nm and 430 nm for bis-and mono-substituted pyrene compounds, respectively. Such blue to violet emission wavelengths are desirable because they are essential for the chromaticity of display and lighting applications; however, there are few examples of violet-blue emitter materials with high ϕ and low thresholds for amplified emission. The number of substituents seems to have a greater impact on shifting the emission wavelength than the conjugation length of the arms. Typically, alkylated fluorene containing substituents ensure high solubility for solution processing as well as a high ϕ and low ASE thresholds. However, endcapping the fluorenesubstituted pyrene stars with either electron donating or withdrawing groups, for example diarylamine or benzonitrile, enables modulation of the ASE threshold. High thermal-and photostability has been observed for several substituted pyrenes, which is a requirement for application as gain medium in organic lasers. Moreover, the comparably high charge carrier mobility reported for some pyrenes may indicate their suitability for electrically driven devices and potential for thicker emission layers that would support laser emission. Despite these promising characteristics, there are currently no pyrene materials that combine both stimulated emission and triplet-to-singlet conversion. Moreover, it is not yet understood how the substitution affects the nature and energy of the excited states.