In organometallic complexes containing π-conjugated macrocyclic chelate ligands, conformational change significantly affects metal−ligand electronic interactions, hence tuning properties of the complexes. In this regard, we investigated the metal−ligand interactions in hexaphyrin mono-Pd(II) complexes Pd[28]M and Pd[26]H, which exhibit a redox-induced switching of Huckel− Mobius aromaticity and subsequent molecular conformation, and their effect on the electronic structure and photophysical behaviors. In Mobius aromatic Pd[28]M, the weak metal−ligand interaction leads to the π electronic structure of the hexaphyrin ligand remaining almost intact, which undergoes efficient intersystem crossing (ISC) assisted by the heavy-atom effect of the Pd metal. In Huckel aromatic Pd[26]H, the significant metal−ligand interaction results in ligand-tometal charge-transfer (LMCT) in the excited-state dynamics. These contrasting metal−ligand electronic interactions have been revealed by time-resolved electronic and vibrational spectroscopies and time-dependent DFT calculations. This work indicates that the conspicuous modulation of metal−ligand interaction by Huckel−Mobius aromaticity switching is an appealing approach to manipulate molecular properties of metal complexes, further enabling the fine-tuning of metal−ligand interactions and the novel design of functional organometallic materials.