The observation of massless Dirac fermions in monolayer graphene has propelled a new area of science and technology seeking to harness charge carriers that behave relativistically within solid-state materials. Using low-temperature scanning tunneling microscopy and spectroscopy, we show the emergence of Dirac fermions in a fully tunable condensed-matter system—molecular graphene—assembled via atomic manipulation of a conventional two-dimensional electron system. Into these electrons we embed, map, and tune the symmetries underlying the two-dimensional Dirac equation. With altered symmetry and texturing, these Dirac particles can be given a tunable mass, or even be married with a fictitious electric or magnetic field (a so-called gauge field) such that the carriers believe they are in real fields and condense into the corresponding ground state. This talk will describe how molecular graphene seeds a versatile path via tailored nanostructures to synthesize novel devices and exotic topological phases in electronic materials.