Our recent high (P,T) developments at PEARL beamline will allow us to study the kinetic and thermodynamic behavior of boron 11B under pressures up to 12 GPa and temperatures up to 2600K. So the principal allotropes of boron could be studied in both pure state and in metallic solvents (to reduce the kinetic inhibition of transformation in solid state). Particular attention will be paid to the synthesis of HP polymorphs (alpha, tetragonal and gamma phases) under HP-HT in our set-up. The expected results are a better understanding and experimental confirmation/refinement of theoretical phase diagram of boron. The applied aspect will be focused on the establishment and optimization of synthesis p-T conditions of HP polymorphs of boron in order to obtain the single crystals, sintered polycrystalline solids and powders.