Magnetic and luminescent properties within a single nanosystem provide a promising platform for cancer theragnostic, combining multiple functionalities in one. The magnetic component permits applications such as magnetic resonance imaging (MRI) and magnetic hyperthermia, improving diagnostic precision and offering a means for localized cancer treatment. The luminescent component aids optical imaging and phototherapy, offering supplementary diagnostic and therapeutic functionality. Together, these properties create a versatile tool that enhances diagnostic accuracy and sensitivity, potentially leading to earlier detection and more effective cancer treatment. Recently, magneto-luminescent nanosystems have revolutionized multimodal imaging and image-guided tumor therapy. This chapter elaborates on the latest advancements in magneto-luminescent nanomaterials, emphasizing their synthesis strategies and applications in cancer diagnostics and treatment. The discussion begins by introducing luminescent and magnetic nanomaterials and their properties used for biomedical applications. Then, examine the methods employed for designing magneto-luminescent nanomaterials and how the magnetic and optical properties interact and vary when coexisting in a single nanosystem. The chapter further explores their functional role in cancer diagnosis, highlighting their use as multimodal imaging probes and therapeutic agents for cancer. Furthermore, recent magneto-luminescent nanomaterials design advancements are discussed, along with the potential challenges associated with clinical translation, providing insights for future research.