The one-pot transmetalation/deprotonation reaction of the bulky triazene Dmp(Tph)N3H with bis(pentafluorophenyl)mercury and europium or ytterbium affords the structurally characterized unsolvated metal(II) pentafluorophenyl triazenides [Dmp(Tph)N3MC6F5] (M = Eu, Yb; Dmp = 2,6-Mes(2)C(6)H(3) with Mes = 2,4,6Me(3)C(6)H(2); Tph = 2-TriPC(6)H(4) with Trip = 2,4,6-(Pr3C6H2)-Pr-i) or, depending on the molar ratio, the solvated complex [Dmp(Tph)N(3)ybC(6)F(5)(THF)].