RNA and protein sequences dictate their structures, spanning multiple length scales, from molecular conformations to patterns of subcellular localization. In turn, these structures govern biological function. Characterizing sequence-structure relationships is critical for gaining mechanistic understanding, but conventional techniques can be slow and low-throughput. We have developed integrated computational and experimental methods to overcome these limitations and have applied them to resolve the three-dimensional structures of a wide range of RNA molecules and RNA-protein complexes, and to systematically reveal the protein sequence features that drive condensate formation in cells. This work paves the way for the development of transformative predictive models of RNA and protein sequence-structure relationships.