The use of a solvothermal process for the synthesis of tantalum carbide (TaC) and lanthanum hexaboride (LaB6) powders in fused-quartz test tubes is reported in order to demonstrate the synthesis of these powders using thermal and chemical ignition techniques and to prove that the process is of a self-propagating high-temperature synthesis type, obviating the need for an autoclave. X-ray powder diffraction showed phase pure powders with crystallite sizes of 25 and similar to 80 nm, while dynamic light scattering showed average particle sizes of 97 and similar to 130 nm, for TaC and LaB6, respectively. The data demonstrates that the powders have a very low level of agglomeration. Scanning electron microscopy shows that the TaC powders have a spherical morphology, while the LaB6 powders have a mixture of cubic and spherical morphologies.