Treatment of titanium tetrachloride with 3,5-di-tert-butylpyrazole affords the complexes [3,5-(C(CH3)(3))(2)C3H3N2](2)-[TiCl6] and (3,5-(C(CH3)(3))(2)C3HN2)(2)TiCl2 in 37 and 42% yields, respectively. An analogous reaction with 3,5-dimethylpyrazole, 3-methylpyrazole, 4-bromopyrazole, and 4-iodopyrazole leads to the formation of corresponding TiCl4L2 binary adducts in 30-86% yields. Crystal structures of [3,5-(C(CH3)(3))(2)C3H3N2](2)[TiCl6], (3,5-(C(CH3)(3))(2)C-3-HN2)(2)TiCl2, TiCl4(3,5-(CH3)(2)C3H2N2)(2), and TiCl4(4-IC3H3N2)(2) were determined. [3,5-(C(CH3)(3))(2)C3H3N2](2)[TiCl6] crystallizes in the space group C2/c with a 18.892(4) Angstrom, b = 7.1200(10) Angstrom, c = 24.461(6) Angstrom, beta = 103.78(2)degrees, and Z = 4. (3,5-(C(CH3)(3))(2)C3HN2)(2)TiCl2 crystallizes in the space group P2(1)/n with a = 12.283(10) Angstrom, b = 17.891(8) Angstrom, c = 12.5 80(6) Angstrom, beta = 90.96(4)degrees, and Z = 4. TiCl4(3,5-(CH3)(2)C3H2N2)(2) crystallizes in the space group C2/c with a 12.087(2) Angstrom, b = 12.922(3) Angstrom, 10.403(2) degrees, beta = 92.08(2)degrees, and Z = 4. TiCl4(4-IC3H3N2)(2) crystallizes in the space group C2/c with a = 9.252(2) Angstrom, b = 8.660(2) Angstrom, c = 19.652(4) Angstrom, beta = 102.14(3)degrees, and Z = 4. An analysis of factors governing the cis/trans geometry of MCl4L2 (M = Ti, Zr, Hf) complexes is offered.