obtained by monitoring the time-evolution of the temperature under laser irradiation at 470 nm with an irradiance of 0.68 W•cm -2 (Figure and Figures ) and the absorption spectra of each compound at the beginning of each photothermal cycle. From those results, it is clear that a photothermal effect is operative and that a correlation exists between the maximum temperature achieved and the donor character of the peripheral group. Indeed, the temperature of the solutions of compounds 6a-c raises from 25 °C to 49-53 °C after 400 s irradiation of a 40 µM solution (Figure -A), while the temperature of irradiated pure DMSO increased by only 1.5 °C under the same conditions. The temperature rise of 6d was even more important reaching 72 °C for a 40 µM solution (Figure ). It should also be noted that no photothermal effect was observed in the case of the 4a-d series, for which the photoisomerization remained the favored deexcitation pathway.