The electronic properties of materials are intimately connected to their atomic structure. The formation of charge density waves (CDWs) and spin density waves in various layered metallic chalcogenides, for instance, directly coincides with a structural phase transition (such as a periodic lattice distortion in the case of CDWs). In the past, studies on monolayer graphene and various semiconducting dichalcogenides have shown that taking layered materials to their physical 2D limit leads to fundamental changes in band structure, allowing for an additional experimental knob to tune for electronic functionality. However, the new structural phases of these atomically thin materials have only been discovered more recently. In this talk, I will focus on graphene and the layered CDW material 1T-TaS2. I will show via transmission electron microscopy how changes in their 2D structure at different length scales (twin boundaries in bilayer graphene, grain boundaries in polycrystalline graphene, and CDW domains in 1T-TaS2) further modify their electronic characteristics, which we correlate using transport measurements. I will discuss the fundamental physics behind such phenomena as well as demonstrate their use in developing novel electronic devices.