The assembly of reticular or net-like materials is governed by solid-state chemistry, but unlike classical solid-state materials, reticular materials are composed of organic building blocks. The design of these organic molecules provides an extraordinary degree of control over the structure and properties of reticular materials. Rather than using this control to create new "well-behaved" and predictable structural outcomes, we introduce competing interactions and incompatible symmetries in the building blocks to induce frustration. The resulting structures from this frustrated assembly exhibit emergent structural features such as non-stoichiometry, distorted building blocks and motifs, and size-limited assembly. These effects can be seen in covalent organic frameworks (COFs), metal organic frameworks (MOFs) and hydrogen bonded frameworks (HOFs). Through the emergence of these structural features, we aim to introduce functionality into reticular materials that is not available in "well behaved" structures.