The development of molecular materials whose physical properties can be switched between different states has attracted significant attention for their potential application in sensing, information processing, spintronics, and smart actuators. Generally speaking, such functional bistability can be induced by the motion of electrons or constituted molecules in response to external stimuli. In this Feature Article, we will introduce how to manipulate the structural variations, including spin crossover, molecular reorientation, and molecular displacement, to tune the magnetic properties, optical properties, dielectric properties, and mechanical response of single-crystal materials, with a highlight of our contributions to this booming field.