A team led by Prof. DOU Xincun at the Xinjiang Technical Institute of Physics and Chemistry of the Chinese Academy of Sciences synthesized a new covalent organic framework (COF)—a crystalline material made of a light element such as carbon, hydrogen, nitrogen, or oxygen, which can be customized at the molecular level. Using the new COF—dubbed tDACH—the researchers inserted cyclohexane-based linkers as conjugation "breakpoints," thereby engineering π-conjugated domains that enable intrinsic exciton confinement at the molecular scale.