Pressure, an intensive variable, is a virtually unexplored pathway to new quantum materials. The application of high pressure can yield dramatic new examples of quantum materials. In this presentation, I will discuss how high pressure can be used to tune unexpected physical properties in magnetic topological materials and low dimensional materials. The use of high pressure and high temperature synthesis can stabilize the exotic quantum phenomena detected by high pressure X-ray and neutron scattering. I will also introduce our new lab-based in-situ high pressure and high temperature single crystal X-ray diffraction technique, which can guide us to synthesize materials rationally under high pressure and high temperature. High pressure synthesis techniques will be the focus of the discussion, novel iridates (Sr_2IrO_4, SrIrO_3), and tetragonal BaCoO_3.