We clearly see the catalytic effect of Au nanoparticles by comparing rate constants of the isomerization reactions occurring in hybrid material with (Au-2) and without Au (no Au). Analysis of the extinction changes at the maximum of the π→π * band plotted as a function of time reveals that both reactions obey first-order kinetics (Figure ), just as free Azo molecules in solution. E-Z and Z-E AzoGly isomerization reactions are enhanced by 52.2% and 48.6%, respectively in the presence of gold (Figure and Figure ). These changes reflect the catalytic influence of AuNRs on directly photoinduced Azo isomerization. We suppose that the catalytic boost occurs via the electron transfer (eT) mechanism, as it has been proposed for Azo photoswitching in the dark in the presence of Au nanospheres. We hypothesize that eT is triggered by UV irradiation addressing interband transitions of AuNRs, which gives rise to the generation of highly energetic carriers. Transfer of those carriers to Azo molecules is reflected in the observed coherent changes of the l-LSPR position upon simultaneously occurring photoisomerization. Both types of hybrid materials (with and without Au) exhibit stable photoswitchability upon interval UV (3 min) and Vis (3 min) irradiation (Figure ). Both isomerizations can be induced and repeated in the materials over many cycles. The intensity of the π→π * band in both photostationary states remains stable over the course of the experiment. This proves that the degradation of photochromic component or material does not occur.