0, 0.2, 0.4, 0.6, 0.8, and 1.0 are prepared by induction melting of the elements and characterized by powder XRD, AC susceptibility measurements, and DSC. All compounds are single phase and crystallize in the body-centered tetragonal ThCr 2 Si 2 -type structure with the space group I4/mmm. Substitution of Pr for Gd causes a linear increase in the lattice constants and the unit cell volume. At low temperatures, the Gd sublattice orders and reconfigures the ordering in the Mn sublattice. The Neel temperature decreases linearly with increasing Pr content x. The x-T magnetic phase diagram is given. -(KILIC*, A.; KERVAN, S.; GENCER, A.; J.