In a quest for precisely sterically tuned ligand systems, the new scorpionate ligands hydrotris(3-cyclopropylpyrazol-1-yl)borate, Tp(Cpr), and tetrakis(3-cyclopropylpyrazol-1-yl)borate, pz*Tp(Cpr), have been synthesized. They readily form octahedral homoleptic and heteroleptic complexes with first-row transition metal compounds, but their [M(Tp(Cpr))(X)] complexes are unstable with respect to the octahedral ones. The complex [Mo(Tp(Cpr))(CO)(2)(eta(3)-CH2CMeCH2)] was also prepared. Structures of the paramagnetic [Co(Tp(Cpr))(2)], [Co(pz*Tp(Cpr))(2)], and [Co(Tp(Cpr))(Tp(Ph))] complexes have been determined by H-1 NMR and those of [Fe(Tp(Cpr))(2)] and [Fe(pz*Tp(Cpr))(2)], as well as that of [Co(Tp(Cpr))(Tp(Ph))], by X-ray crystallography, indicating facile accommodation of six cyclopropyl groups in the equatorial belt of octahedral complexes. In its coordination behavior, Tp(Cpr) is quite different from Tp(iPr) and resembles Tp(Me).