Used as a selective inhibitor of nitric oxide synthase (NOS), particularly inducible NOS (iNOS), in research settings to study the role of nitric oxide in inflammatory and immune responses. Helps in investigating conditions like septic shock, arthritis, and other inflammatory diseases by modulating NO levels. Also employed in plant physiology studies to delay senescence and improve stress tolerance in crops. Serves as a reagent in organic synthesis for the preparation of heterocyclic compounds and functionalized guanidines.