This book highlights and investigates novel solid-state luminescent properties of crystals with stimuli-responsive behavior. Several novel molecular designs for controlling crystal structures with photo-physical properties are described, with a special focus on external stimuli-responsive properties.  The major goal of the material design concept was to capitalize on the chirality of crystals with stimuli-responsive properties. To allow crystals’ chirality to be controlled and modified by means of external stimulation, the axial chirality of biaryl moiety was employed and, interestingly, produced several novel mechano- and vapo-responsive luminescent properties based on crystal-to-crystal or single-crystal-to-single-crystal phase transitions. In addition, the book details how the molecular rotation of luminophores in the solid phase can be used to achieve corresponding thermal-responsive phosphorescence.    The reports presented here illustrate how the author has succeeded in controlling structural factors in a bulk environment by using molecular design with linking to photo-physical properties. The content will be of great interest to researchers in the field, and to members of chemical and material science societies.