Molecular design and preparation of bis-isophthalate electrochromic systems having controllable color and bistability.

New electrochromic systems based on bis-isophthalates were designed and prepared. They showed electrochromism behavior by two-electron reduction. The displayed colors showed greatly enhanced bistability and were dependent on the length of the conjugated bridge between the two isophthalate groups. We believe that the connection of two electrochromic systems with a conjugated bridge is a good basic strategy to obtain new bistable electrochromic systems.