Abstract Cardanol, a well known hazardous byproduct of the cashew industry, has been used as starting material for the synthesis of useful differently substituted “cardanol-based” porphyrins and their zinc (II), copper (II), cobalt (II) and Fe (III) complexes. Novel composites prepared by impregnation of polycrystalline TiO 2 powder with an opportune amount of “cardanol-based” porphyrins, which act as sensitizers for the improvement of the photo- ...