Due to the rapid developments of technologies related to terahertz (THz) spectroscopy, quick and precise measurements have become possible in the THz frequency region (0.1 -10 THz or 3 -333 cm -1 ), in which organic materials show characteristic spectra (so-called fingerprint spectra). Since those absorption bands are mainly due to the intermolecular vibrational motion, THz spectroscopy provides detailed information about intermolecular structures and intermolecular interactions such as hydrogen bondings. Especially for macromolecules, THz spectra give direct information about higher order conformation and hydrogen bonding networks, all of which play an important role for their physical and chemical properties. Therefore, THz spectroscopy is poised to become a powerful tool for research in polymer science.