Inorganic Chemistry teaches students the concept that modifications to ligand structures, especially the donor properties, can have a drastic impact on the reactivity and stability of the metal complexes. Experiments described here reinforce this concept through the investigation of two tetradentate ligands derived from "o"-phenylenediamine and salicylaldehyde. The Schiff base ligand, H[subscript 2]salophen, reacts with Ni(OAc)[subscript 2]·4H[subscript 2]O to yield a maroon, square planar complex, Ni(salophen). Under the same conditions, the amine-type ligand, H[subscript 2]salophan, forms a light-blue compound analyzed as [Ni(Hsalophan)(OAc)][subscript 2]. The Ni(salophan) complex free of acetate may be produced from the reaction of H[subscript 2]salophan with Ni(OAc)[subscript 2]·4H[subscript 2]O in the presence of NaOH but undergoes ligand dehydrogenation to yield Ni(salophen). Students conducting these experiments have the opportunity to learn synthetic techniques and various characterization methods. Most importantly, the inquiry-guided experimental design helps them develop critical thinking skills and apply acquired knowledge to solving a research problem in a laboratory course.