Without doubt, topochemical reactions play an important role for our current batteries, e.g., within oxide-based cathode materials or carbon-based anode materials for lithium-ion batteries. However, topochemistry of oxide materials is by no means restricted to small cations, and perovskite as well as perovskite-related materials possess a vivid insertion chemistry for anions, making them interesting compounds for a broad range applications related to their multitude of functional properties, among them magnetism and superconductivity. In this talk, the use of topochemical reactions with anions to develop and understand new energy materials with tailored and tunable properties will be highlighted. These reactions cover the preparation of oxyfluorides and oxyhydroxides for fluoride-ion batteries and electrocatalytic (SOFC and PCFC) applications. Special focus will be set on using topochemistry for the reversible on/off-switching of material properties. Last but not least, the impact of anion and vacancy ordering on the intrinsic properties will be given, with a special focus on barium ferrates and cobaltates with perovskite-related structure, for which novel compounds could be prepared and structurally characterized.