Selecting specific 2D building blocks and specific layering sequences of van der Waals heterostructures should allow the formation of new materials with designed properties for specific applications. Unfortunately, the synthetic ability to prepare such structures at will, especially in a manner that can be manufactured, does not exist. Herein, we report the targeted synthesis of new metal–semiconductor heterostructures using the modulated elemental‐reactant technique to nucleate specific 2D building blocks, control their thickness, and avoid epitaxial structures with long‐range order. The building blocks, VSe2 and GeSe2, have different crystal structures, which inhibits cation intermixing. The precise control of this approach enabled us to synthesize heterostructures containing GeSe2 monolayers alternating with VSe2 structural units with specific sequences. The transport properties systematically change with nanoarchitecture and a charge‐density wave‐like transition is observed. Layered cake: The modulated elemental‐reactant technique provides a unique route to the targeted synthesis of new van der Waals heterostructures. VSe2 and GeSe2 were selected as 2D building blocks to inhibit cation intermixing. The kinetic control offered by this approach enabled heterostructures with varying stacking sequences to be prepared.