The prevalence of HCN in many astrochemical environments, and its reactive nature, places the molecule, and its possible reaction products, center stage of prebiotic chemistry and astrobiology. However, a clear picture of HCN reactivity, both in laboratory and in astrochemical environments, remains elusive. HCN-derived polymers are complex materials that can form under a variety of laboratory conditions. These product mixtures are typically heterogeneous and insoluble in most common solvents. Various forms of characterization have been attempted to elucidate which chemical 3 structures can form from HCN. For example, mass spectrometry, infrared and nuclear magnetic resonance (NMR) spectroscopy have been used to infer a wide variety of functional groups in polymerization product mixtures. A plethora of different polymerization pathways have been proposed to explain this complexity (see ref. for a review). Due to their diverse nature, some HCN-derived polymers are functional materials with proposed uses in catalysis, as adhesives and as coatings. The complex space of HCN-derived chemistry. For this analysis, we have collected HCN-based materials that appear as suggestions, hypotheses, or confirmed detections, in literature.