This work presents an overview of a series of increasingly complex oxides synthesized from CrO2, under high-pressure and high-temperature conditions, having Cr4+ in octahedral coordination. Although the emphasis is on the structure and microstructure of the compounds as obtained from X-ray diffraction and transmission electron microscopy and diffraction, attention is also given to their interesting electronic and magnetic properties. The study is complemented with an electron energy loss spectroscopic analysis of the different phases. These are the cubic perovskite SrCrO3, the orthorhombic perovskite CaCrO3, the solid solution Sr1-xCaxCrO3, the Ruddlesden−Popper-type Sr3Cr2O7, the family CrSr2RECu2O8 (RE = rare earth), a compositionally modulated perovskite “PbCrO3”, and the misfit layer oxide SrO2[CrO2]1.85.