Three isomeric pyridine-containing diarylethenes were synthesized to study the effects of nitrogen atom position (ortho, para, meta) on their photochromic properties. Among these diarylethenes, the example with the nitrogen atom at the ortho-position of pyridine displayed the largest absorption maximum and molar absorption coefficients. The cyclization quantum yields increased in order of para< meta< ortho, whereas their cycloreversion quantum ...