<p>This review examines the development of fluorescent sensors based on cellulose/carbon quantum dot (CQD) composites. We focus on sustainable “bottom-up” synthesis utilizing agricultural waste as both a carbon precursor and a functional structural scaffold. Integrating CQDs into cellulose matrices consistently overcomes aggregation-caused quenching (ACQ), resulting in stabilized optical signals and enhanced mechanical properties. Current trends show a shift toward heteroatom doping (N, S) to improve selectivity. These composites demonstrate high sensitivity in detecting heavy metal ions, foodborne pathogens, and environmental pollutants across diverse formats, including flexible films, hydrogels, and electrospun fibers. Future research must address batch-to-batch variability in biomass precursors and signal interference in complex real-world matrices. The integration of multi-scale computational screening with solid-state sensor architectures is expected to facilitate the transition from laboratory prototypes to scalable, commercial diagnostic platforms.</p> Graphical abstract <p></p>