  Fabrication of ordered structures at the nanoscale limit poses a cornerstone
challenge for modern technologies. In this work we show how naturally occurring
moir\'e patterns in Ir(111)-supported graphene template the formation of 2D
ordered arrays of substitutional boron species. A complementary experimental
and theoretical approach provides a comprehensive description of the boron
species distribution, bonding configurations, interfacial interaction with
Ir(111) and the impact on graphene's electronic structure. Atomically-resolved
scanning tunnelling microscopy images and density functional theory
calculations reveal that boron preferably forms small aggregates of
substitutional defects in geometrically low regions of the moir\'e superlattice
of graphene, by inducing local bending of graphene towards the underlying
Ir(111). Surprisingly, calculations reveal that the incorporation of electron
deficient boron does not lead to an enhanced p-type doping, as the local
rippling of the graphene layer prompts electron uptake from the iridium
substrate that compensates the initial electron loss due to substitutional
boron. Scanning tunnelling spectroscopy and angle-resolved photoemission
spectroscopy measurements corroborate that the arrays of boron species do not
modify the electronic structure of graphene near the Fermi level, hence
preserving the slight p-type doping induced by Ir(111).
