The high entropy boride (HEB) of Al0.2Nb0.2Pt0.2Ta0.2Ti0.2B2 was synthesized using an aluminum molten flux growth. Pure elemental powders were combined with an additional 10 mmol of aluminum powder, which acted as the flux (typical loading values are listed in Table ). The powders were stoichiometrically ground in an agate mortar and pestle and mixed uniformly with acetone. After the acetone evaporated, the resulting mixture was pressed into a 10 mm diameter pellet and placed in an alumina boat. The alumina boat was then introduced into a Lindberg Blue tube furnace capable of reaching 1000℃. A titanium rod was positioned upstream in the furnace to act as an oxygen getter at high temperatures, thereby further protecting the sample from oxidation. Throughout the entire heating process, a constant, slow flow of argon was maintained to create an inert atmosphere for the duration of the heating cycle. The thermal treatment followed the profile: an initial 6-hour room temperature purge to eliminate adsorbed water and oxygen, heating to 1000℃ at a rate of 5℃/min, a 24-hour hold at 1000℃, and finally, cooling back to room temperature at a rate of 5℃/min. At the conclusion of the heating cycle in the tube furnace, the pellet was etched by immersing the pellet in 6 M NaOH in an ice bath for 48-hours to remove the aluminum flux. Following this, the sample was centrifuged at 4000 RPM for 3 minutes, and the top 25 mL layer was discarded. The sample was replenished to 30 mL with deionized water, this washing step was repeated three times. Next, the sample underwent three additional washed with 15 mL of acetone each time to ensure the removal of any remaining aqueous residue. Finally, the sample was placed in a vacuum oven and dried for four hours to ensure complete removal of moisture.