Heterogeneous catalysis, Hybrid materials, Nanoparticles, Porous magnesium oxide, Twin polymerization The yellow and white road signs on the left symbolize the synthesis of the respective twin monomers with the tornado standing for their polymerization. Keywords: Heterogeneous catalysis; Hybrid materials; Nanoparticles; Porous magnesium oxide; Twin polymerization EN Heterogeneous catalysis Hybrid materials Nanoparticles Porous magnesium oxide Twin polymerization 1 1 1 03/27/23 20230317 NES 230317 B The Front Cover b illustrates the twin polymerization of [Mg(2-OCH SB 2 sb - SP I c i sp C SB 6 sb H SB 4 sb O)][L] SB n sb forming interpenetrating inorganic-organic hybrid materials, which, upon thermal treatment, produce porous magnesium oxides. [Extracted from the article]