Molecular devices incorporating azobenzene units represent active components of smart systems, as they are capable of exhibiting photoregulated cooperative molecular motion. Herein, we describe the synthesis, X-ray crystal analysis, and photochemical and thermal studies of a xanthene based cyclic azobenzene dimer and its precursor. The trans-trans isomer of the azobenzene dimer upon photoirradiation transforms to the cis-cis isomer ...