The synthesis, spectroscopy, and structure of transition-metal coordination compounds of the ligand bis[2-(3,5-dimethyl-1-pyrazolyl)ethyl]amine (abbreviated ddaH) are described. The ligand acts as a tridentate Ns-donor Ligand in the compounds [M(ddaH)Cl](2)(MCl(4)) with M = CU2+, Co2+, and Zn2+, and in the compounds [M(ddaH)-Cl](BF4) with M = CU2+ and Co2+ as shown spectroscopically and - in a selected number of cases - proven by X-ray diffraction. The compound [Cu(ddaH)Cl](2)(CuCl4) crystallizes in the monoclinic space group C2/c (Z = 4). The cell dimensions are a = 23.207(9) Angstrom, b = 11.614(5) Angstrom, c = 14.408(4) Angstrom, beta = 90.26(4)degrees, V = 3883(2) Angstrom(3), D-x = 1.584 g/cm(3), and R = 0.056 (R(W) = 0.058) for 1765 significant reflections. The copper(II) ion in the cationic part is surrounded by two pyrazole nitrogens (Cu-N distances are 1.999(8) and 1.980(7) Angstrom) and an amine nitrogen (Cu-N distance is 2.022(7) Angstrom) from the ligand and by one chloride anion (Cu-Cl distance is 2.232(3) Angstrom) in a distorted tetrahedral coordination geometry. The compound [Co(ddaH)Cl](2)(CoCl4) crystallizes in the monoclinic space group C2/c (Z = 4). The cell dimensions are a = 20.810(7) Angstrom, b = 13.429(3) Angstrom, c = 14.284(2) Angstrom, beta = 92.53(2)degrees, V = 3988(2) Angstrom(3), D-x = 1.519 g/cm(3), and R = 0.040 (R(W) = 0.052) for 2825 significant reflections. The cobalt(II) ton in the cationic part is surrounded by two pyrazole nitrogens (Co-N distances are 2.004(3) Angstrom and 1.982(3) Angstrom) and an amine nitrogen (Co-N distance is 2.068(3) Angstrom) from the ligand and by one chloride anion (Co-Cl distance is 2.216(1) Angstrom) in a distorted tetrahedral coordination geometry. The anionic part of both compounds consists of a distorted tetrahedral tetrachlorometalate(II) with a Cu-Cl distance of 2.215-2.282 Angstrom, a Co-Cl distance of 2.255-2.289 Angstrom, a Cl-Cu-Cl bond angle of 100.8-137.0 degrees, and a Cl-Co-Cl bond angle of 104.1-116.4 degrees. There is a moderately strong hydrogen bridge between the (MCl(4))(2-) anion and the amine nitrogen of the ligand ddaH. The shortest distances from the (MCl(4))(2-) anion to the M(2+) in the cation are 4.26 Angstrom and 3.673 Angstrom for respectively Co2+ and Cu2+. The compound [Cu(ddaH)Cl](BF4) crystallizes in the orthorombic space group Pbca (Z = 8).