The Graphene/O2DC heterostructures on substrates dataset, identified by DOI 10.17172/NOMAD/2025.07.28-1, contains computational simulation data for various carbon-based molecular and material systems. Authored by Shuangjie Zhao, Miroslav Polozij, and Thomas Heine, the dataset includes entries for complex chemical formulas involving C, H, N, O, Si, and B. The data comprises DFT single-point simulations performed using FHI-aims, as well as geometry optimization simulations conducted using DFTB+. The collection is relevant for applications such as solar cells and heterogeneous catalysis, providing essential electronic and structural property calculations for graphene and two-dimensional covalent organic framework heterostructures on substrates.