Graphene quantum dots (GQDs) are attractive materials for use as highly selective and sensitive chemical sensors, owing to their simple preparation and affordability. GQDs have been successfully deployed as sensors...

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The Buchwald−Hartwig cross-coupling reaction between 4-methylumbelliferone-derived nonaflates with amides, carbamates, and sulfonamides is described. A wide variety of Nsubstituted 7-amino coumarin analogues was prepared in good to excellent yields. The photophysical properties of aqueous-soluble derivatives were determined, and they displayed auxochrome-based variations. Gram-scale synthesis provided an acrylamide analogue, which was used to fabricate a fluorescent poly(2-hydroxylethyl methacrylate) (pHEMA) hydrogel that was resistant to leaching in ultrapure H 2 O. We envisage that our reported protocol to access 7amino-4-methylcoumarin derivatives will find use toward the development of new fluorescent coumarin-based probes by researchers in the field.