The synthesis of multiarm star block (and mixed-block) copolymers are efficiently prepared by using Cu(I) catalyzed azide-alkyne click reaction and the arm-first approach. alpha-Silyl protected alkyne polystyrene (alpha-silyl-alkyne-PS) was prepared by ATRP of styrene (St) and used as macroinitiator in a crosslinking reaction with divinyl benzene to successfully give multiarm star homopolymer with alkyne periphery. Linear azide end-functionalized poly(ethylene glycol) (PEG-N-3) and poly (tert-butyl acrylate) (PtBA-N-3) were simply clicked with the multiarm star polymer described earlier to form star block or mixed-block copolymers in N,N-dimethyl formamide at room temperature for 24 h. Obtained multiarm star block and mixed-block copolymers were identified by using H-1 NMR, GPC, triple detection-GPC, atomic force microscopy, and dynamic light scattering measurements. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 99-108, 2010