Abstract:　Near-infrared　(NIR)　light-responsive　materials　had　attracted　much　attention　by　virtue　of　their　ability　to　employ　abundant　light　sources　to　adapt　their　properties　remotely　and　spatially　in　which　development　of　novel　NIR　light-responsive　fillers　was　the　key　factor.　In　this　work,　cellulose　nanocrystals　(CNCs)　were　coated　with　polydopamine　(PDA)　to　endow　these　plant-derived　nanofillers　with　good　light　absorption　properties.　In　this　work,　PDA@CNC　was　incorporated　into　the　poly(N-isopropylacrylamide)　(PNIPAM)　matrix　to　fabricate　PDA@CNC/PNIAPM　nanocomposite　hydrogels　with　controllable　performance　in　response　to　NIR　stimuli.　The　PDA@CNC　would　not　only　serve　as　a　reinforcement　agent　to　mechanically　toughen　the　hydrogels　but　also　integrate　considerable　photothermal　effect　into　the　same　system.　As　a　result　of　fast　NIR　responsiveness　and　easily　tailored　photothermal　properties,　the　5-Fluorouracil　(5-Fu)　release　behavior　of　the　nanocomposite　hydrogels　could　be　remotely　controlled　with　the　assistance　of　a　NIR　laser.　Besides,　the　nanocomposite　hydrogel　with　Ag　nanoparticles　immobilized　PDA@CNC　(Ag/PDA@CNC)　was　demonstrated　as　a　novel　catalyst　to　tune　the　reduction　rate　of　4-nitrophenol　(4-NP)　upon　NIR　irradiation.　Taken　together,　the　modified　CNCs　would　be　alternative　functional　nanofillers　for　the　construction　of　NIR　light-responsive　materials　with　controllable　performance.　Graphic　abstract:　[Figure　not　available:　see　fulltext.].　©　2021,　The　Author(s),　under　exclusive　licence　to　Springer　Nature　B.V.　part　of　Springer　Nature.