Cover story: Sulfoxides are essential structural motifs in pharmaceuticals and fine chemicals. Selective aerobic oxidation of sulfides (SAOS) is an important photochemical transformation for the synthesis of sulfoxides from sulfides. We developed nanostructured polyphenothiazene (PPTZ) through a single-step polymerization of phenothiazine (PTZ), which narrows the band gap from ~3.56 eV to ~2 eV for efficient visible-light absorption. Varying the oxidizing agent tunes PPTZ nanoparticle morphology and photocatalytic performance. As a metal-free photocatalyst, PPTZ drives SAOS under visible light, delivering up to 99% conversion and >99% selectivity. Thus, PPTZ nanomaterials emerge as promising visible-light catalysts for green pharmaceutical production.

Gogoi, R.; Jena, S. K.; Singh, A.; Sharma, K.; Kumar, R.; Siril, P. F. Metal-Free Conjugated Polyphenothiazine Nanostructures as Visible Light Active Photocatalyst for Selective Aerobic Oxidation of Sulfides. Photocatalysis 2026, 2 (1), 1. https://doi.org/10.53941/photocatalysis.2026.100001.