Carbon nanofibers (CNFs) have attracted significant interest because of their excellent mechanical, electrical, and physical properties. Recent advances in chemical functionalization strategies are anticipated to extend their utility in various applications. In this study, noncovalent methods of CNF functionalization utilizing solution crystallization and precipitation techniques were used to create hybrid nanostructures consisting of CNFs and poly(butylene terephthalate) (PBT). Key to this study is the finding that o-chlorophenol can be used as a suitable solvent to dissolve PBT to generate these nanostruclures. PBT crystallization was documented via wide-angle X-ray analysis and differential scanning calorimetry and was due to the nucleation effect of the CNFs. The sizes of the PBT crystals could be manipulated by altering the polymer concentration. The solution crystallization and precipitation techniques provide an alternative strategy to alter and control the nanostructure/polymer interface. The resulting nanohybrid structures may potentially find use in a broad range of applications including electronic devices, sensors, and as reinforcing agents in a polymer matrix. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 1312-1319, 2009