We report the growth of a single crystal of PrIr3B2 by Czochralski pulling method and its structural and anisotropic magnetic properties. At room temperature, PrIr3B2 crystallizes in the hexagonal CeCo3B2-type (P6/mmm) structure. However, a change of crystal symmetry is indicated by a hysteretic transition observed in both the resistivity and heat capacity taking place at ≈ 280 K, which is similar to the observed transition from monoclinic (at room temperature) to hexagonal at 395 K previously reported in CeIr3B2 in literature. The jump in the heat capacity at the transition during cooling is nearly 400 J/mol K. The Curie-Weiss behavior of susceptibility conforms to a trivalent state of the Pr ions, which order antiferromagnetically or ferrimagnetically, as inferred from a relatively broad peak in the susceptibility centered around 10 K. The bulk magnetic transition is further corroborated by an anomaly in the heat capacity at low temperatures. Both the temperature dependence of magnetization, and the isothermal magnetization at 2 K reveal a highly anisotropic magnetic behavior in PrIr3B2 with c-axis [0001] as the hard direction of magnetization. The electrical resistivity shows normal metallic behavior down to TN, below which it shows an upturn suggesting the onset of superzone gap. © 2019 Author(s).