Nevertheless, strong enrichment of either state could be achieved in the pss when using four different wavelengths of light irradiation. When starting from 93%/84% 1-Z/2-E and irradiating with 385 nm light 94%/64% 1-E/2-E was obtained. Subsequent irradiation with 730 nm resulted in a 90%/99% 1-E/2-Z mixture and a following irradiation with 450 nm light resulted in 93%/41% 1-Z/2-Z. Finally, irradiation with 590 nm led to the starting isomeric distribution 93%/82% 1-Z/2-E again. To improve this performance, we then changed the irradiation conditions so that two different wavelengths are used simultaneously for each state accumulation (Figure ). This resulted in very high-performing all-photon orthogonal photoswitching yielding reproducibly 97%/85% solution, which result in an effective four-color photochromic behavior, i.e. cyan for 1-Z/2-E, bright green for 1-E/2-E, brown green for 1-E/2-Z, and a blue purple for 1-Z/2-E (Figure ).