The phosphodiester backbone imparts nucleic acids a high negative charge density. In the presence of polymeric cations, DNA and RNA undergo charge-mediated phase separation called complex coacervation. I will show that base pairing can be used to program the macroscopic properties of nucleic acid coacervates, and thus generate mesoscale materials with sequence-programmable properties. The addressability of base pairing can also be used to produce self-sorting multi-phase coacervates with an arbitrary number of coexisting liquid-like phases. This work showcases how sequence-specific intermolecular-RNA hybridization could program the properties of RNA-containing granules in cells, and provides a quantitative framework to connect interaction energies to coacervate properties.