Dark quencher molecules are now regarded as key components in the design of smart optical bioprobes, especially those that rely on Förster resonance energy transfer (FRET), currently used in protease activity assays, nucleic acid hybridization, and real‐time polymerase chain reactions (PCRs). In responding to growing demand of these bio-logic molecules, we are open to custom-make these dark quencher molecules to certain customers according to your specific specifications. For illustration proposal, QSY21 acid, QSY21 NSH and other common molecules are exampled below.