The first early transition metal tris(methimazolyl)borate complexes [M(=NR)Cl-2{HB(mt)(3)}] (M = Nb, Ta; R = C6H3Pr2-2,6; mt = methimazolyl) have been obtained from the reactions of [Nb(=NR)Cl-3(DME)] or [Ta(=NR)Cl-3(THF)(2)] (DME = dimethyl ether; THF = tetrahydrofuran) with Na[HB(Mt)(3)] and structurally characterized, illustrating that the HB(Mt)(3) ligand can indeed be compatible with "hard" metals in high oxidation states.