A　G-rich　nucleic　acid-tethered　acrylamide/N-isopropylacrylamide　(NIPAM)　copolymer　is　prepared.　The　nucleic　acid-modified　pNIPAM　chains　assemble,　in　the　presence　of　K+　ions,　into　a　stimuli-responsive　G-quadruplex-crosslinked　pNIPAM　hydrogel　undergoing　cyclic　and　reversible　solution/hydrogel/solid　transitions.　Addition　of　kryptofix　[2.2.2],　CP,　to　the　K+-stabilized　G-quadruplex-crosslinked　hydrogel　eliminates　the　K+　ions　from　the　crosslinking　units,　resulting　in　the　transition　of　the　hydrogel　into　a　pNIPAM　solution.　In　turn,　heating　the　pNIPAM　hydrogel　from　25°C　to　40°C　results　in　the　transition　of　the　hydrogel　to　the　solid　state,　and　cooling　the　solid　to　25°C　restores　the　hydrogel　state.　Incorporation　of　hemin　into　the　G-quadruplex-crosslinked　hydrogel　results　in　a　catalytic　hydrogel　that　catalyzes　the　oxidation　of　aniline　by　H2O2　to　form　polyaniline.　The　polyaniline/pNIPAM　hydrogel　hybrid　doped　with　2　M　HCl　forms　an　emeraldine　salt,　which　exhibits　an　electrical　conductivity　of　9　×　10-4　[cm　Ω]-1.　©　The　Royal　Society　of　Chemistry.