We prepared a core-shell structured nanogel composed of carbon nanodots (C-dots), fluorescein, and poly(N-isopropylacrylamide) (PNIPAM) via emulsion copolymerization. The hybrid nanogel material was responsive to temperature as an emissive hybrid material and showed reversible and ratiometric changes in fluorescence emission according to temperature cycles at 25 and 45 A degrees C, resulting from the shrinking of the PNIPAM copolymer chains with temperature variation. Dynamic light scattering, transmission electron microscopy were used to characterize the morphology and size of the particles. The hybrid nanogel was sensitive enough to temperature to be promising in biological application, such as temperature-sensitive drug delivery system and bioimaging.