Photochromism has attracted considerable attention because of its potential application in molecular devices, such as optical memories and switches.1,2 Among various thermally irreversible photochromic compounds, diarylethene derivatives are the most promising compounds because of their fatigue resistant proper- ty.3 Recently, 1-aryl-1,3-butadiene derivatives4,5 and bis(2,30- benzothienyl) derivatives6 have been reported to show thermally irreversible ...
