Fig. 3. UV/vis absorption spectra of E-P1 upon (a) irradiation with 340 nm light and (b) subsequent irradiation with 405 nm light in THF (3.00 × 10⁻⁵ M). (c) ¹H NMR spectra (500 MHz, THF-d₈) of E-P1, Z-P1, and PSSs under 340 and 405 nm irradiation in THF-d₈ (1.00 × 10⁻⁴ M). (d) UV/vis absorption spectra and (e) changes in absorbance at 344 nm upon alternating irradiation of E-P1 with 340 and 405 nm light in THF (3.00 × 10⁻⁵ M).