All MONs were synthesized using an adaptation of previously established methods. Briefly, Ni 2+ was sonicated together with terephthalic acid or its derivatives to assemble layered structures containing sheets NiO6 octahedra. Four types of Ni-MONs were synthesized and named in accordance with the type of linker used (terephthalic acid -Ni-MON; tetrafluoroterephthalic acid -Ni-F-MON; hydroxyterephthalic acid -Ni-OH-MON, aminoterephthalic acid -Ni-Amine-MON). The aim here was to have the electron donating or withdrawing groups on the linker modulate the electronic structure and consequently, catalytic performance of the Ni active sites for the oxygen reduction reaction. Following synthesis and purification, the materials were characterized with a host of techniques. First infrared spectroscopy showed revealed strong bands around 1600-1700 (C=O stretch) for all MONs, revealing the presence of terephthalate (Fig. ). Next, X-ray diffraction (XRD) was employed to characterize the crystallinity of the MONs (Fig. ). While the Ni-MON and Ni-Amine-MON assembled into the expected phase [no. 985792, Cambridge Crystallographic Data Centre], the Ni-OH-MON remained largely amorphous as its smaller grain size did not lead to strong diffraction peaks. However, electron diffraction measurements did indicate a weak degree of crystallinity that could be observed (Fig. ). Further, the Ni-F-MON assembled into a layereddouble hydroxide (LDH) structure. However, as the F-component was detected throughout the material via elemental mapping through transmission electron microscopy (TEM) measurements (Fig. ) we believe that the linkers were confined to the outer portion of the MON instead. Atomic force microscopy (AFM) was then used to provide another layer of structural information (Fig. and S3-7). The measurements reveal all of the materials to possess a flakelike morphology and thicknesses on the order of 10 nm. TEM images (Fig. and S8-11) further show that the MONs featured a rough morphology. Finally, x-ray photoelectron spectroscopy (XPS) was utilized to measure the electronic structure of the Ni components. The Ni 2p3/2 peaks for all MONs are shown in Fig. and slight shifts in their binding energy roughly match the electron donating/withdrawing nature of the functional groups on the terephthalate ligands, with a 0.31 eV separation between the peaks of the Ni-F-MON and Ni-Amine-MON.