A novel family of azobenzene-based photochromic amorphous molecular materials has been created. They were found to readily form amorphous glasses with well-defined glass-transition temperatures and to exhibit photochromism as amorphous films as well as in solution. It was found that their quantum yields of transâcis photoisomerization were smaller as amorphous films than in solution and that the backward cisâtrans thermal isomerization reactions as amorphous films were either accelerated or retarded relative to those in solution, depending upon their molecular structures. In addition, the rate acceleration for the cisâtrans thermal isomerization as amorphous films relative to solution was found to be more prominent as the irradiation time for generating the cis-isomer became shorter.