The first example of Diels-Alder cycloaddition of ortho-xylylenes to meso-tetraarylporphyrins containing electron-deficient β,β-double bonds

β-Nitro-meso-tetraphenylporphyrin and the 2,7-dinitro-derivative, or their zinc complexes, react with ortho-xylylenes, giving rise to chlorins, bacteriochlorins or isobacteriochlorins.