We report on the synthesis of telechelic poly(N-isopropylacrylamides) (PNIPAM) via nitroxide-mediated controlled polymerization, putting a focus on the introduction of defined end group moieties into telechelic poly(N-isopropylacrylamide) and poly(n-butyl acrylates). Various functional groups, linked to the central nitroxide-initiator via a triazole moiety resulting from an azide/alkyne-"click" reaction were probed with N-isopropylacrylamide and n-butyl acrylate as monomers in terms of efficiency and livingness. Functional groups on the initiator include a 1,2-dihydroxyalkyl moiety and a barbituric acid moiety as well as a phenyl moiety. Those initiators with a 1,2,3-1H-triazole moiety directly bound to the initiator group displayed a poor initiating quality toward N-isopropylacrylamide, whereas an ester bridge as linker between the initiator molecule and the functional group showed highly living character with respect to N-isopropylacrylamide and n-butyl acrylate as probed by kinetic experiments. Effects based upon internal hydrogen-bonding effects are made responsible rather than purely stereoelectronic effects, as proven by force-field calculations. MALDI time-of-flight mass spectrometry was used to prove the incorporation of the respective end groups into the telechelic PNIPAM polymers. Finally, the versatility of the method was demonstrated via a "grafting-from" approach of PNIPAM from magnetic iron oxide nanoparticles via a surface-bound initiator, resulting in an excellent control of molecular weight and thus thickness of the polymeric shell around the magnetic nanoparticles.