Our group has  also reported hypervalent  tin-fused azobenzene (TAz) compounds (Figure 1) [1‒3]. From a  series of mechanistic  studies, it has been  clarified that the  coordination of the N  atom to the tin atom and  the electron donation  from the O atom to the π-  system simultaneously  caused stabilization of the lowest unoccupied molecular orbital energy level and  elevation of the highest occupied molecular orbital energy level, achieving a narrow  energy gap. Moreover, TAz can formed stable higher-coordinated structures, which  changed the electronic state and the absorption and emission wavelengths. However,  the planar structure of the π-planes of TAz caused critical aggregation-caused  quenching. In this study, we attempted to give excitation-driven property to hypervalent  tin compounds to develop aggregation-induced emission molecules showing emission  in the longer wavelength region only in the solid state [4]. We focused on azomethine  structure, which allows to be introduced substituents at the C=N position. The steric  hindrance originating from the substituent causes distortion in the molecule and  promotes intramolecular vibration. Based on this idea, we designed and synthesized  three types of hypervalent tin-fused azomethine compounds with different substituents (H, Me, and Ph) and explored researched the differences in optical properties derived  from the substituents. Furthermore, we attempted to application to thermal sensors  using the polymers containing the hypervalent tin-fused azomethine units compounds  in the backbone.