The terminal alkyne homocoupling reaction (oxidative alkyne coupling) is presented here as a new route for the preparation of A(2)B(2) type 4-miktoarm star copolymer. The block copolymer with terminal alkyne at the junction point prepared by NMP-ATRP and ROP-NMP sequential routes is coupled via diyne formation to give (PS)(2)-(PMMA)(2) and (PCL)(2)-(PS)(2) 4-miktoarm star polymers, respectively, by using a combination of (PPh3)(2)PdCl2/PPh3/CuI in a solvent mixture of Et3N/CH3CN at room temperature for 72 h. The molecular weight, intrinsic viscosity ([eta]), radius of gyration (R-g), and hydrodynamic radius (Rh) of A(2)B(2) 4-miktoarm star copolymers were calculated using triple-detection GPC as results of three detectors response. (D 2008 Wiley Periodicals, Inc.