The title compound, [Fe(C9H10BN6)2], is a polymorph of a compound reported previously [Oliver et al. (1980). Inorg. Chem. 19, 165–168]. In the previous report, the compound crystallized in the monoclinic space group P21/c (Z = 4), whereas the crystal symmetry of the compound reported here is tetragonal (P42/ncm, Z = 4). The molecular structure is comprised of two hydrotris(1-pyrazolyl)borate ligands (Tp−) and a central FeII ion, which is coordinated by six pyrazole N atoms from two two Tp− ligands, yielding a distorted bipyramidal FeN6 geometry. The complete molecule exhibits symmetry 2/m