Theranostics have been used to describe image-guided therapy or therapeutic agents that simultaneously possess imaging capabilities. We focus on developing theranostics agents, with the incorporation of a specific targeted therapy, such as Photothermal Therapy (PTT) that can be assisted with a powerful diagnostic tool, Magnetic Resonance Imaging (MRI). We are interested in coordination complexes and nanoparticles with transition metals and lanthanides. The type of photothermal agent that we are developing are nickel bis-dithiolenes complexes, which have been proved as photothermally active systems that absorb near Infra-red light and convert it to heat to nucleate the cancer cells. The incorporation of a paramagnetic metal to our systems will confer the capability as contrast agents for cancer detection using the MRI technique. Our main goal is to contribute to the scientific community in the health area making our research a contribution to this field.