3-Methoxyphenyl isocyanate is primarily used as a key intermediate in the synthesis of various organic compounds, particularly in the production of pharmaceuticals and agrochemicals. It is often employed in the development of active pharmaceutical ingredients (APIs) due to its reactivity with amines, alcohols, and other nucleophiles, forming urethanes, ureas, and other derivatives.

In the agrochemical industry, it serves as a building block for creating pesticides and herbicides, where its isocyanate group facilitates the formation of carbamates and other functionalized molecules. Additionally, it is utilized in the production of specialty chemicals, such as dyes and coatings, where its ability to form stable bonds with other compounds enhances material properties like durability and adhesion.

Its application extends to research and development, where it is used in organic synthesis to explore new chemical reactions and pathways, contributing to advancements in chemical science.