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We report on the fabrication of hybrid silica nanoparticles densely grafted with thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) brushes with inner and outer layers selectively labeled with fluorescence resonance energy transfer (FRET) donors, 4-(2-acryloyloxyethylamino)-7-nitro-2,1,3-benzoxadiazole (NBDAE), and photoswitchable acceptors, 1′-(2-methacryloxyethyl)-3′,3′-dimethyl-6-nitro-spiro(2H-1-benzo-pyran-2,2′-indoline) (SPMA), respectively, via surface-initiated sequential atom transfer radical polymerization (ATRP). P(NIPAM-co-NBDAE)-b-P(NIPAM-co-SPMA) brushes at the surface of silica core exhibit collapse in the broad temperature range of 20−37 °C. UV irradiation of the aqueous dispersion of hybrid silica nanoparticles induces the transformation of SPMA moieties in the outer layer of polymer brushes from nonfluorescent spiropyran (SP) form to fluorescent merocyanine (MC) form …