Pyrido[3,4-d]pyrimidine-2,4(1H,3H)-dione is primarily utilized in pharmaceutical research and development. It serves as a key intermediate in the synthesis of various biologically active compounds, particularly those targeting enzyme inhibition. Its structure is often incorporated into molecules designed to interact with specific proteins or enzymes, making it valuable in drug discovery efforts. Additionally, it is explored for its potential in developing treatments for diseases such as cancer, inflammation, and microbial infections due to its ability to modulate cellular pathways. Researchers also study its derivatives for their therapeutic properties, aiming to optimize efficacy and reduce side effects in medicinal applications.