Neutron scattering is a powerful experimental technique which is comprehensive with calorimetry. For the last 20 years, we have carried out both adiabatic calorimetric and various neutron scattering experiments. In the adiabatic calorimetry, the measurements of heat capacity and enthalpy of absorption have been carried out. In the neutron scattering, powder diffraction, inelastic scattering, and quasielastic scattering techniques have been utilized, each providing structural, excitation and relaxational information. The present article shows several examples of the works on phase transitions of hydrogen-bonded systems, hydrogen absorption and interstitial-sites occupation in palladium nanocrystals, low-energy excitations (boson peaks) in vapor-deposited simple molecular glasses, and diffusion dynamics of imidazolium-based ionic liquids. These examples clearly show the complementarity between the calorimetry and neutron scattering.