The final step of the porphyrin-forming process is dehydrogenation of the intermediate. Various oxidizing agents are commonly used, from atmospheric oxygen in Adler's reaction in refluxing propionic acid to p-chloranil or 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) under milder conditions. Polypyrromethenes, the major side products, are usually easily separated, but the removal of the reduction products of the organic oxidizing agents requires tedious chromatography. We have replaced the organic oxidants with pyridinium chlorochromate, easily prepared from CrO 3 , hydrochloric acid and pyridine. The products of its reduction are easily separated by adsorption on silica and the desired porphyrin is extracted with dichloromethane.