Abstract We fabricated stable hybrid monolayers of an anionic azobenzene and alkylammonium, while pure azobenzene did not form a stable monolayer. Efficient photoisomerization of azobenzene proceeded in the Langmuir-Blodgett films due to salt formation of the two components, allowing azobenzene to have free volume with alkylammoniums as spacers. Keywords: alkylammoniumanionic azobenzeneLangmuir-Blodgett filmphotoisomerization