Pharmaceutical Field
4-Hydroxycoumarin is a key intermediate for the synthesis of anticoagulant drugs. The hydroxyl group and lactone ring in its structure provide an active basis for the design of drug molecules. Coumarin anticoagulants, represented by warfarin, inhibit the synthesis of vitamin K-dependent coagulation factors and block the blood coagulation process. They are often used to prevent and treat thromboembolic diseases (such as deep vein thrombosis and atrial fibrillation). In addition, the derivatives of this compound can be used as structural templates for anticoagulants. By modifying the hydroxyl group or lactone ring, the efficacy of the drug can be optimized, the risk of bleeding can be reduced, and the safety of the drug can be improved.

Pesticide and Rodenticide Field
In the field of pesticides, 4-Hydroxycoumarin is an important raw material for the preparation of anticoagulant rodenticides. Typical products include sodium diphacin and chlorfenapyr. This type of rodenticide destroys the coagulation function of mice and causes them to die from internal bleeding. It has the characteristics of slow action and good palatability, which can prevent mice from having a food refusal reaction and achieve efficient rodent control. Compared with acute rodenticides, anticoagulant rodenticides based on 4-hydroxycoumarin have lower toxicity to non-target organisms and are less likely to cause secondary poisoning, which meets the needs of environmentally friendly pesticides.

Fluorescent Materials and Sensors
4-hydroxycoumarin can be used as a structural skeleton of fluorescent probes due to its conjugated system and hydroxyl functional groups, and is used to prepare highly sensitive fluorescent materials. Its derivatives can specifically bind to metal ions (such as Fe³⁺, Cu²⁺) or biomolecules (such as enzymes and proteins) by introducing specific groups (such as amino groups and thiol groups), triggering changes in fluorescence intensity or wavelength, thereby realizing the detection of environmental pollutants and biomarkers. For example, fluorescent sensors containing 4-hydroxycoumarin can be used for real-time monitoring of heavy metal ions in water bodies, or imaging analysis of reactive oxygen species in cells.

Organic Synthesis Intermediates
As a multifunctional organic intermediate, the hydroxyl group and lactone ring of 4-hydroxycoumarin can participate in a variety of chemical reactions and are used to construct complex organic molecules. For example, coumarin derivatives can be prepared through esterification of hydroxyl groups, which are used in the synthesis of fragrances and sunscreens; amino groups, alkyl groups and other groups can be connected through the ring-opening reaction of the lactone ring to prepare compounds with anti-inflammatory and antioxidant activities. In addition, its parent core structure can be used as a precursor for heterocyclic synthesis, and condensed ring compounds can be constructed through cycloaddition, coupling reactions, etc., which are used in drug development and functional material preparation.

Dye and Optical Material Field
4-hydroxycoumarin derivatives can be used as the core structure of dye molecules. Because their conjugated system can absorb and emit light of specific wavelengths, they are often used to synthesize fluorescent dyes, laser dyes, etc. For example, in dye lasers, some 4-hydroxycoumarin derivatives can be used as gain media to generate tunable laser radiation; in biological fluorescence labeling, by modifying hydroxyl groups to introduce active groups (such as carboxyl groups, maleimide), dyes can be coupled to proteins or nucleic acids for cell imaging and biomolecule tracking.