Novel non-aqueous thermochromic solutions were facilely prepared by dissolving transition metal chlorides, such as NiCl2·6H2O, CrCl3·6H2O, FeCl3, and CoCl2·6H2O, in an inexpensive, widely available ionic liquid analogous deep eutectic solvent (DES). It was found that only the NiCl2·6H2O dissolved choline chloride-based DES exhibited a stable and significant thermochromic behavior over a wide working temperature ranging from room temperature to about 150 °C. Typically, the colour of the 0.1 M NiCl2·6H2O dissolved DES solution changed in this order from pale green (room temperature), spring green (∼70 °C), to blue (∼120 °C). An effective strategy was proposed to produce more thermochromic solutions by mixing Ni(II) with other metal ions in the choline chloride-based DES. The thermochromic PVDF composite film was demonstrated by incorporating DES-based Ni(II) solution into the microporous PVDF film. The preliminary results are expected to stimulate interest of the development of high performance thermochromic materials for the facile fabrications from DESs.