Z-5n, Z-6n and E-7n absorb light in a visible and UVA region. Irradiation of Z-5n, Z-6n and E-7n with the blue (470 nm), purple (430 nm) or ultraviolet light (365 nm) in THF leads to substantial changes in the absorption and emission profiles (Figure ). This is in agreement with photoswitching about their double bonds leading to E-5n, E-6n and Z-7n, respectively. One minute of irradiation is sufficient to reach the photostationary states (PSS), whose compositions were established by NMR (for NMR samples longer irradiation times were required due to higher sample concentration). Thermal reversibility of the process was monitored by UV and FL, and, in all cases full recovery was detected. It is also important to note, that compounds Z-5n, and Z-6n are fluorescent, and florescence is switched-off upon photoswitching.