A nanocomposite was fabricated using poly(vinylidene fluoride) (PVDF) as matrix and poly(p-chloromethyl styrene) (PCMS) grafted with high dielectric constant copper phthalocyanine oligomer (CuPc) (PCMS-g-CuPc) as filler. Transmission electron microscopic morphologies reveal that the PCMS-g-CuPc particle size of ca. 80 nm in average are dispersed in PVDF matrix, while in PCMS-g-CuPc particles the PCMS acts as "matrix" which contains dispersed CuPc balls with a average size of ca. 25 nm [1/20 of that of CuPc in simple blend of PVDF and CuPc (PVDF/CuPc)]. The nanocomposite with only 15 wt% CuPc can realize a dielectric constant of 325 at 100 Hz, about 7 times larger than that of PVDF/CuPc, and nearly 40-fold enhancement with respect to that of the pure PVDF. The significant enhancement of dielectric response can be attributed to the remarkably strengthened exchange coupling effect as well as the Maxwell-Wagner-Sillars polarization mechanism. (C) 2008 Elsevier Ltd. All rights reserved.