▎ 摘　　要

Graphene quantum dots (GQDs) derived from lignin, which is the most naturally abundant aromatic biopolymer on earth, have found promising application in many fields. Here, we demonstrate that GQDs with concentration dependent photoluminescence emission can be produced from lignin by employing a non-oxidative method. In brief, o-aminobenzenesulfonic acid was used as an acidic hydrotrope for lignin depolymerization, followed by a conventional hydrothermal treatment. Detailed investigations indicated that the observed concentration dependent feature for GQDs was attributed to the stack of graphene basal plane and the interaction of functional groups. Moreover, it was found that the concentration-dependent emissive GQDs were endowed with ultralong-term photostability (12 months) and negligible cytotoxicity, promising them potential applications in anti-counterfeiting and bioimaging. Overall, this study develops a feasible and sustainable strategy for opening up enormous opportunities to use renewable lignin-derived GQDs for more technological applications.