H-shaped quintopolymer containing different five blocks: poly(epsilon-caprolactone) (PCL), polystyrene (PS), poly(ethylene glycol) (PEG), and poly(methyl methacrylate) (PMMA) as side chains and poly(tert-butyl acrylate) (PtBA) as a main chain was simply prepared from a click reaction between azide end-functionalized PCL-PS-PtBA 3-miktoarm star terpolymer and PEG-PMMA-block copolymer with alkyne at the junction point, using Cu(I)/N,N,N',N '',N '',-pentamethyldiethylenetriamine (PMDETA) as a catalyst in DMF at room temperature for 20 h. The H-shaped quintopolymer was obtained with a number-average molecular weight (M-n) around 32,000 and low polydispersity index (M-w/M-n) 1.20 as determined by GPC analysis in THF using PS standards. The click reaction efficiency was calculated to have 60% from H-1 NMR spectroscopy. (c) 2008 Wiley Periodicals, Inc.