A well-defined amphiphilic coil-rod block copolymer, poly(2-vinyl pyridine)b-poly(n-hexyl isocyanate) (P2VP-b-PHIC), was synthesized with quantitative yields by anionic polymerization. A low reactive one-directional initiator, potassium diphenyl methane (DPM-K), was very effective in polymerizing 2-vinyl pyridine (2VP) without. side reactions, leading to perfect control over molecular weight and molecular weight. distribution over a broad range of initiator and monomer concentration. Copolymerization of 2VP with n-hexyl isocyanate (HIC) was carried out in the presence of sodium tetraphenyl borate (NaBPh4) to prevent backbiting reactions during isocyanate polymerization. Terminating the living end with a suitable end-capping agent resulted in a P2VP-b-PHIC coil-rod block copolymer with controlled molecular weight. and narrow molecular weight distribution. Cast film from a chloroform solution of P2VP-b-PHIC displayed microphase separation, characteristic of coil-rod block copolymers. (C) 2004 Wiley Periodicals, Inc.