under the same conditions, and the absorption spectra were recorded during 5 cycles. All 6a-d compounds present good photostability as their temperature gain (DT) remains slightly constant with a decrease of only 10% after 5 cycles (Figure -A) while DCM recorded a decrease of 52% after one cycle and of 72% after 5 cycles (Figure ). UV-Vis analyses revealed a slight chemical modification of compounds 6a-d (Figure -C and S17), either due to photodegradation or to photoisomerization under high irradiance. DCM exhibits even more dramatic evolution of the UV-Vis spectrum (Figure -D), probably due to its isomerization, as already reported in the literature or to a higher photodegradation. This also leads to the diminution over irradiation time of the DCM absorption at irradiation wavelength (470 nm), which contribute to its lower photothermal conversion efficiency as compared to 6d.