Cu2ZnSnS4 is a p-type semiconductor that has been seen as a possible replacement for SnSe, Cu (In,Ga)Se2 etc. in thin film solar cells, due to non-toxicity and natural abundance of their constituent elements. Polycrystalline Cu2ZnSnS4 samples (kesterite-type) were synthesized by a microwave assisted method and investigated by inelastic neutron scattering. The experimentally measured neutron-weighted phonon density of states compares reasonably well with that estimated by a computation of the lattice dynamics. These studies are then extended to elucidate the understanding of the thermal, elastic and thermoelectric properties. The lattice-dynamics calculations are able to reproduce the temperature dependence of the thermal conductivity and the thermoelectric figure of merit, as observed in experiments previously.