A series of dinuclear metal terpyridine (M-tpy; M = Flu, Os, Fe, and Cc) complexes with a photochromic dithienylethene bridge were designed and synthesized through either a convergent or a divergent approach. The open forms of the complexes containing Ru-II and Fe-II centers were found to be inert to ultraviolet photoirradiation but could be cyclized electrochemically as revealed by a cyclic voltammetric study. On the contrary, the Coll complex underwent efficient photochemical but not electrochemical cyclization. The corresponding Os-II complex was neither photochromic nor electrochromic.