N3-Methylthymidine is primarily used in biochemical research as a modified nucleoside to study DNA structure and function. It serves as a tool to investigate the effects of methylation on DNA replication and repair mechanisms. Researchers utilize it to understand how methylation at specific sites influences gene expression and cellular processes. Additionally, it is employed in the development of nucleoside analogs for antiviral or anticancer therapies, as it helps in exploring the role of modified nucleosides in inhibiting viral replication or cancer cell proliferation. Its application extends to studying epigenetic modifications and their impact on biological systems.