N-salicylidineanilines are known to show thermochromic behaviour, which is currently postulated to arise from an intramolecular proton shift between the keto and enol form as the temperature is reduced. However, over the relevant temperature range (120-280 K), our current combined variable temperature X-ray and solid state NMR studies on N-(3-chloroaniline)-3-methoxy-salicylaldimine, 1, N-(3-chloroaniline)-4-methoxy-salicylaldimine, 2 and N-(3-chloroaniline)-5-methoxy-salicylaldimine, 3, have shown no change in the either the compound structure or atomic chemical environments respectively. In order to gain crucial insights into the thermochromic mechanism for these compounds, we aim to conduct variable temperature neutron diffraction experiments on 1, 2 and 3 to accurately determine the hydrogen positions and determine whether any such proton shift occurs.