The photooxidation process to artemisinin was studied in detail using different types of light sources by conversion of dihydroartemisinic acid (DHAA) or related derivative into artemisinin using tetraphenylporphyrin (TPP) as photosensitizer in the presence of oxygen. The pivotal singlet oxygen was generated by illumination of the reaction mixture during bubbling ambient air by means of either a mercury vapour lamp or light emitting diodes with appropriate wavelengths focusing on the absorption maximum of the TPP. Both light sources resp. methods were compared, in efficiency, yield and resulting quality of isolated artemisinin. These photooxidation studies in laboratory scale were investigated and kinetically monitored using ATR-MID-IR- and UV/Vis spectroscopy as process analytical tools (PAT). Due to the sensitive endoperoxide containing structure of artemisinin and potential peroxide containing by-products the safety aspect was intensively examined particularly with regard to scaling up the photooxidation process. Beyond technical requirements for future realisation of LEDs as light source in production scale were considered. (C) 2016 Elsevier B.V. All rights reserved.