3,4-Dicyanophenol is an organic compound featuring a phenol ring substituted with two cyano groups at the 3 and 4 positions. This bifunctional structure, containing both a phenolic hydroxyl group and electron-withdrawing cyano groups, makes it a versatile building block in materials chemistry. Its primary application is as a key precursor in the synthesis of advanced organic electronic materials. It is notably used in the preparation of high-performance electron-transporting materials (ETMs) and host materials for organic light-emitting diodes (OLEDs). The cyano groups are crucial for enhancing electron affinity and tuning the energy levels of the resulting materials, which is essential for improving device efficiency and stability. Additionally, due to its reactive phenolic and cyano functionalities, it serves as a valuable intermediate in organic synthesis for constructing more complex conjugated systems, particularly in the field of functional dyes and polymers.