(E)-3-Ethoxyacrylic acid is primarily used as an intermediate in organic synthesis, particularly in the production of pharmaceuticals and agrochemicals. It serves as a key building block in the synthesis of various compounds, including active pharmaceutical ingredients (APIs) and crop protection agents. Its unique structure allows for the introduction of ethoxy and carboxylic acid functional groups into target molecules, enabling the development of compounds with specific biological activities. Additionally, it is employed in the preparation of fine chemicals and specialty materials, where its reactivity and versatility are leveraged to create complex molecular architectures.