YbAl3C3 undergoes a structural phase transition at 80 K and a spin-dimer formation below 10K. To gain more information on the nature of the spin-dimer state and the phase transition, we have carried our inelastic neutron scattering (INS) study on MARI (RB920300). Our INS study clearly reveals the presence of two well defined magnetic excitations at 1.5 and 3meV at 4K and one broad excitation at 1.8meV at 10K. Further we have seen a dramatic change in the high energy (between 40 and 45meV) response across the structural phase transition at 80K as well as between 4K and 15K. At present a detail structural model for the low temperature phase and its temperature dependent is not available, which is important to understand the INS excitations. We therefore propose to carry out high resolution neutron diffraction investigations on YbAl3C3 using HRPD to understand our INS data.