An unsupported microspherical ReS2 catalyst, consisting in self-assembled nano-layers, was evaluated in the hydrodesulfurization (HDS) of 3-methylthiophene showing an excellent catalytic activity. The samples were characterized by X-ray diffraction, scanning electron microscopy, high resolution electron microscopy, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. These techniques revealed that the rhenium disulfide layers are confined to a 3D hierarchical structure with different stacking, slab size and bending, according to the annealing temperature (400 or 800 A degrees C). The presence of a defect-rich structure in the microspheres, with short and randomly-orientated ReS2 slabs, results in the exposure of additional edge sites, which improve the catalytic performance of this material. This microspherical ReS2 composite, with good HDS performance, is a promising catalyst for the desulfurization of fuel oils; the solvothermal reaction conditions are also useful to tune and create exotic morphologies for the design of new ReS2 catalysts.