As opposed to inorganic counterparts, organic quantum dots often exhibit lower fluorescence efficiencies and are complex to synthesize. Here we develop nitrogen‐doped (N‐GQDs) and nitrogen–sulfur codoped (NS‐GQDs) graphene quantum dots exhibiting high‐yield visible and near‐IR emission that are synthesized via a single‐step microwave‐assisted hydrothermal technique with a single glucosamine‐HCl starting material (thiourea precursor used for NS‐GQDs). As‐synthesized N‐GQDs and NS‐GQDs are well‐dispersed (average sizes of 5.50 and 3.90 nm) with high crystallinity and pronounced G‐band. Formed by the bottom‐up assembly of glucosamine, they contain amine linkage and a variety of oxygen‐containing functional groups assessed by Fourier‐transform infrared spectroscopy with ≈2% sulfur for NS‐GQDs. The synthetic procedure allows varying their size and the bandgap. Unlike other graphene‐based quantum dots, these GQDs exhibit bright, stable fluorescence both in the visible and near‐IR with high quantum yields of up to 60%. Excitation‐dependent visible fluorescence is attributed to size‐dependent bandgaps, with near‐IR emission potentially arising from the emissive defect states/their arrangements. Advantageous properties of these GQDs are utilized to develop exciton recombination layer for organic light‐emitting devices exhibiting both photoluminescence and electroluminescence in the visible. Produced by ecofriendly one‐step scalable synthesis brightly‐emissive N‐GQDs and NS‐GQDs become a promising material for novel organic optoelectronics. Nitrogen‐doped and nitrogen–sulfur codoped graphene quantum dots are synthesized by a one‐step scalable microwave‐assisted hydrothermal method. The quantum dots show excitation‐dependent bright and stable fluorescence in the visible and NIR regime with quantum yields up to 60%. These quantum dots are further used to fabricate light‐emitting diodes that exhibit electroluminescence with high current density and moderate turn‐on voltage.