To develop light-induced secret coatings, a side-chain liquid crystal polymer containing photoisomerizable AIEgen (PAP) was newly synthesized. Based on the results of microscopic and scattering analyses, it was found that PAP has smectic mesophase over a wide temperature range due to flexible backbone. The photoisomerization of cyanostilbene in PAP occurs easily at room temperature, which results in phase transition as well as transmittance and luminescence changes. Furthermore, PAP can be self-crosslinked by the dehydrocoupling and oxidation reaction with Pt catalyst. Combining light-induced optical changes and self-crosslinking, light-induced secret and photopatternable optical coatings were demonstrated. This work has big potential to security coatings and patterned optical films. This work was supported by BRL Program (2020R1A4A1018259), Mid-Career Researcher Program (2016R1A2B2011041), Basic Science Research Program (NRF-2019R1A6A3A13092060) funded by the Ministry of Education.