Crystals of the pyrazolylgallium dimethyl dimer (1a) are monoclinic, a = 16.914(3), b = 21.747(6), c = 8.117(2) Å, β = 92.09(3)°, Z = 8, space group P21/c, those of the 3-methyl-pyrazolylgallium dimethyl dimer (1b) are also monoclinic, a = 13.473(6), b = 7.162(2), c = 18.468(4) Å, β = 113.78(2)°, Z = 4, space group P21/c, and those of the indazolylgallium dimethyl dimer (1c) are orthorhombic, a = 8.909(2), b = 27.463(3), c = 15.738(2) Å, Z = 8, space group Pbca. All three structures were solved by Patterson and Fourier methods and were refined by full-matrix least-squares methods to final R values of 0.065, 0.061, and 0.036 for 2542, 2011, and 1986 reflections with I ≥ 3σ(I) respectively. The three crystal structure analyses emphasize the critical role of steric interaction in determining the molecular geometry for these molecules. The results clearly demonstrate that changing deuterium for methyl groups on the gallium atoms and introducing substituents on the bridging 'pyrazolyl' ligands in the [D2Ga·N2C3H3]2 dimer cause a pronounced flattening of the central Ga—(N—N)2—Ga boat conformation and a noticeable lengthening of the Ga—N bonds. Average Ga—N distances are 1.996, 1.986,1.996 Å, and V-angles (the angle between the Ga2N2C3 moieties) are 131.5,139.5, and 147.8° in 1a, 1b, and 1c respectively.