Poly(cytidylic acid) is primarily used in research and biomedical applications due to its ability to mimic RNA structures. It serves as a model for studying RNA interactions, particularly in the context of viral replication and RNA-protein binding. In immunology, it is employed to stimulate immune responses, as it can act as a synthetic analog of viral RNA, triggering pathways like the activation of toll-like receptors. Additionally, it is utilized in the development of vaccines and antiviral therapies, where its properties help in understanding and enhancing immune system activation. Its role in nucleic acid research also extends to exploring gene expression and RNA-based therapeutic strategies.