The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adom.202201644. devices, which have been initially developed in recent years. OLETs combine the current amplification function of organic field-effect transistors (OFETs) with the electroluminescence properties of organic light-emitting diodes (OLEDs). [4][5][6][7][8][9][10] The unique operating mechanism of OLETs makes them widely recognized as one of the ideal key components for the development of next-generation transformative display technologies and the realization of organic electrically pumped lasers. In particular, the electroluminescence of unencapsulated OLETs can be directly observed in real time, which provides an ideal platform for gaining insight into the device physics of charge injection, charge transport, and carrier recombination.Since Hepp et al. [11] reported the first OLET device with an active layer of tetracene (Tc) film in 2003, OLETs have garnered increasing attention from academia and industry. Currently, the development of OLETs is slow, and device efficiency, particularly for single-component devices, is generally low. [12][13][14] The external quantum efficiency (EQE) values of single-component OLETs devices are mostly below 1%. One of the main reasons for the low EQE of OLETs is the lack of highperformance active material. Field-effect modulation and electroluminescence functions are integrated into OLET devices simultaneously; therefore, the active materials of OLETs must possess both high carrier transport and strong luminescence properties. However, these two properties are difficult to realize simultaneously in one molecule because they require contradictory molecular structures and molecular stacking. [15][16][17][18][19][20] Encouragingly, owing to the efforts devoted in recent years, significant breakthroughs have been achieved in the design and synthesis of high-mobility emissive materials. A series of high-mobility emissive material systems have been developed, which provide rich alternatives for the construction of high-efficiency OLET devices. [21][22][23][24][25][26][27][28] Currently, research on OLETs mainly focuses on the development of active materials, optimization of device structures, and characterization of operating properties. The active layers for OLET devices include solution-processed films, thermally evaporated films, and organic semiconductor single crystals. Some excellent reviews have summarized the advanced progress of OLET devices in terms of materials, device structure, display functions, and operating characteristics, [12,[29][30][31] but reviews focusing on single-crystal light-emitting transistors are currently scarce. Long-range ordered organic semiconductor single