Zintl-phase ${\mathrm{EuCd}}_2{\mathrm{As}}_2$ attracts much research interest because it has a potential of manifesting various ideal topological states under external parameters. Here, measurements of resistance, magnetization, Hall, and synchrotron x-ray diffraction at high pressures up to 50.8 GPa in diamond anvil cells are performed on high-quality ${\mathrm{EuCd}}_2{\mathrm{As}}_2$ single crystals that display a long-sought intrinsically insulating antiferromagnetic (AFM) ground state. From ambient pressure to 21.0 GPa, the AFM state of ${\mathrm{EuCd}}_2{\mathrm{As}}_2$ is stable and the AFM transition temperature of $\sim 9.5$ K is raised linearly at a rate of $\sim 1.90$ K/GPa. Meanwhile, the insulating conduction behavior is maintained despite that the whole resistance decreases remarkably. Beyond $\sim 24.0$ GPa, a ferromagnetic-like metallic state shows up, due to a trigonal $P\overline{3}m1$ to monoclinic $C2/m$ structural transition, and its transition temperature of $\sim 150$ K increases linearly at a rate of $\sim 0.69$ K/GPa. This high-pressure magnetic metallic state dominates over the pristine AFM insulating one upon completion of the structural transition around 40 GPa. Based on the present data, we construct a temperature-pressure phase diagram for the intrinsically insulating antiferromagnet ${\mathrm{EuCd}}_2{\mathrm{As}}_2$, which offers essential insights into the pressure-dependent evolutions of magnetic and transport properties and will stimulate further exploration of the interplay among magnetism and transport, as well as nontrivial topology rooted in their interactions.

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• Hall effect
• Pressure effects
• Topological phases of matter
• Magnetization measurements
• Resistivity measurements
• X-ray diffraction