“…The dimers dissociate to the radicals upon irradiation, heating, and trituration. Similar properties have been obtained in crystals of 4,5-bis-(4-methoxyphenyl)-2-(4-nitrophenyl) imidazolium acetate dihydrate that show rapid color change upon drying, trituration, or heating. , 4,5-Bis(methoxyphenyl)-2-(4-nitrophenyl)-1 H -imidazole and 4,5-bis(methoxyphenyl)-2-(3-nitrophenyl)-1 H -imidazole form, with different guest molecules, a wide variety of inclusion compounds of different colors, changing from yellow to black. Kaftory et al described the thermochromic properties, crystal structure, and thermal behavior of inclusion compounds of 4,5-diphenyl-2-(4-nitrophenyl)-1 H -imidazole and 4,5-diphenyl-2-(2-hydroxy-5-nitrophenyl)-1 H -imidazole.…”