Hybrid materials based on Mesoporous Silica Nanoparticles (MSN) have attracted plentiful
attention due to the versatility of their chemistry, and the field of Drug Delivery Systems (DDS) is not
an exception. MSN present desirable biocompatibility, high surface area values, and a well-studied surface
reactivity for tailoring a vast diversity of chemical moieties. Particularly important for DDS applications
is the use of external stimuli for drug release. In this context, light is an exceptional alternative
due to its high degree of spatiotemporal precision and non-invasive character, and a large number of
promising DDS based on photoswitchable properties of azobenzenes have been recently reported. This
review covers the recent advances in design of DDS using light as an external stimulus mostly based
on literature published within last years with an emphasis on usually overlooked underlying chemistry,
photophysical properties, and supramolecular complexation of azobenzenes.