One-Pot Sequential Knoevenagel-Aza-Annulation Strategy for the Synthesis of Peripherally Fused <i>N</i>-Aryl-2-pyridonoporphyrins

One-pot sequential Knoevenagel-aza-annulation pathways allowed direct access to π-conjugated peripherally fused <i>N</i>-aryl-2-pyridonoporphyrins in appreciable yields. The unveiled cascade methodology involves a reaction between 2-formyl-<i>meso</i>-tetraarylporphyrins and 3-hydroxy-3-(2-hydroxyphenyl/1-hydroxynaphthalen-2-yl)-<i>N</i>-arylacrylamides, generated <i>in situ</i> by treating 4-hydroxycoumarin/4-hydroxy-2<i>H</i>-benzo[<i>h</i>]chromen-2-one with anilines in DMF at 150 °C to afford desired porphyrins within 4 h. The SCXRD analysis of porphyrin (<b>4a</b>) revealed a nonplanar structure with intramolecular π-π stacking and hydrogen bonding features. New porphyrins exhibited significantly red-shifted absorption and emission after a peripheral fusion.