Two salicylidene dinitrophenylhydrazine compounds (1 and 2) were synthesized by solid-state reaction of (2,4-dinitrophenyl)hydrazine with 2-hydroxybenzaldehyde and 2-hydroxy-1-naphthaldehyde at room temperature, respectively. Their structures were characterized by elemental analysis, ESI-MS and IR and thermochromism properties were investigated by differential scanning calorimetry spectra. The results exhibited that both 1 and 2 displayed significant colour changes relying on temperature, which can be ascribed to the structural transformation between enol and keto forms in the solid state. This transformation may benefit from the intramolecular hydrogen bond and proton H-transfer.