Nanomaterials have recently received significant attention as photothermal agents and fluorescence contrast agents for molecular therapeutics due to their unique optical properties (e.g. light absorption). In particular, single-walled carbon nanotubes (SWNTs) have been recently utilized as photothermal agents (for photothermal therapy) because of the solubility of SWNTs as well as their light absorbing capability at the near-infrared region. In this work, we have developed the SWNT-based photothermal agents using pyrene-based PEGylation of SWNTs. FT-IR and/or H-NMR spectroscopies have validated the PEGylation of SWNTs, and it is shown that water-soluble SWNTs are able to generate heat under near-infrared (NIR) irradiation of 5W/cm2. Moreover, it is found that our pyrene-based PEGylated SWNTs exhibit the fluorescence characteristic under the excitation wavelength of 340 nm. Our study sheds light on the pyrenyl PEGylated SWNTs as photothermal agents and/or fluorescence contrast agents for the future applications in molecular therapeutics.