Abstract A series of new photochromic compounds were obtained for the first time from 1, 2- bis (2-ethylthio-3-thienyl) perfluorocyclopentene by substituting bromine atoms or carboxy, alkoxycarbonyl, and carbamoyl groups for hydrogen atoms in positions 4 and 4′. Introduction of these substituents causes a slight bathochromic shift (by 20–30 nm) of a long- wavelength absorption band for the cyclic form and significantly increases the quantum ...
