The coordination chemistry of the hexadentate bispidine ligand L1 with two tertiary amine, three pyridine and a pyridazine donor with CuII and ZnII is reported. The substitution of one of the two cis‐disposed pyridine donors in‐plane with the two tertiary amines of the bispidine backbone by a pyridazine group was predicted to substantially reduce distortion from planarity of the tetradentate subunit and therefore was assumed to lead to higher CuII complex stability. The X‐ray single crystal structures of the ZnII and CuII complexes, which are in excellent agreement with the DFT‐ and MM‐optimized structures, confirm this prediction but indicate that deviation from planarity still is appreciable. This also emerges from solution spectroscopy (UV‐vis‐NIR and EPR of the CuII complex) which indicate that the in‐plane ligand field is only slightly increased. The geometric parameters together with the lower basicity of pyridazine vs. pyridine (pKa = 2.33 vs. 5.23) are also in agreement with an only slightly more negative redox potential of the CuII/I couple (Eo = ‐780 mV vs. ‐760 mV, MeCN, vs. Fc/Fc+), and the potentiometrically determined CuII stability constant with L1 in fact is slightly lower than that with the parent ligand L2 (log K = 12.7 vs. 14.5). Therefore, modification of the donor groups, is a more promising way to increase the complex stabilities and yield 64CuII chelators that outperform the already well‐behaved hexadentate bispidine ligands known so far.