The narrow band-gap IV-VI semiconductors have attracted renewed interest due to their various interesting properties viz. phase-change properties, thermoelectricity, topological effects etc. Recently ultralow thermal conductivity and high thermoelectric figure of merit have been found in SnSe single crystals that may find use in waste thermal energy conversion to useful electrical energy. This has motivated us to study the phonon and soft mode dynamics close to the high temperature structural phase transition temperature in SnSe. This study will help us how ultralow thermal conductivity and high thermoelectric figure of merit have been found in SnSe is related with the anharmonicity and soft mode dynamics. We request 7 days of neutron beam time on the triple-axis spectrometer IN8 for the proposed experiment.