Abstract: | The non‐photochromic fulgide (1‐Z) has been successfully converted into the highly photochromic ( 3‐Z ) analogue. A dicyanomethylene group was introduced at the 5‐position of 1‐Z in order to enhance the latter's conjugation properties that would facilitate the photochemical Z→E isomerization process. The irradiation of the product 3‐Z with a UV light at λmax 350 nm formed a bluish green solution which absorbed at λmax 620 nm, corresponding to the ring‐closed product 4. The latter was also formed from the reference dicyanomethylene product 3‐E synthesized from 1‐E. The irradiation of 4 at λmax 532 nm produced the reversion to the original pale yellow color of 3‐E. |