Crystallization of oligomers was applied for the preparation of single-walled carbon nanotubes (SWNTs)/poly(p-oxybenzoyl) (POB) crystals using SWNTs as a nucleating agent. Polymerization conditions were investigated to induce the crystallization of POB oligomers through SWNTs. SWNTs/POB plate-like or lozenge-shaped crystals were successfully prepared by direct polymerization of p-hydroxybenzoic acid (HBA) in a mixed solvent of DMF/Py with TsCl in the presence of functionalized. SWNTs. The size of the plate-like crystals were similar to 200 nm to 3 mu m. The crystals consisted of some layers, similar to 3 nm thick plates. Model reactions showed that esterification reactions proceed between functionalized SWNTs and HBA monomers in the polymerization system. The obtained crystals exhibited unique morphology and high crystallinity, producing a novel SWNT/POB hybrid. (C) 2008 Wiley Periodicals, Inc.