We report on the successful attempt to synthesize thermoresponsive nanodiamonds hybrid microgels through a straightforward method. Resulting microgels exhibit smart properties, as the reversible collapsing of the structures when raising the temperature, with embedded nanodiamonds. Thanks to the colloidal and smart properties of the microgels, nanoscaled 2D self-assembled arrays of nanodiamonds with varying inter-particle distances were realized, without any lithographic processes, as an illustration of the promising properties of these novel diamond-based microgels. Such assemblies can constitute a first step toward a bottom–up elaboration of innovative diamond-based devices.