Development of bimodal systems with signals for two diagnostic technique has been increasing. Magnetic resonance imaging (MRI) is a non-invasive technique that distinguish pathological from healthy tissues. To improve the images contrast, nanoparticulate contrast agents (CAs) have been developed, allowing the attachment of several CA molecules in on nanoparticle. In this work, we associated AgInSe₂ quantum dots (QDs) with gadolinium complexes, obtaining nanoprobes for MRI and optical imaging. The nanosystems showed good optical properties and values of relaxivity superior to the CAs used clinically. Thus, these nanoprobes have the potential to be used as CAs for MRI and optical imaging.