Résumé : Coherent states have been long known for their applications in quantum optics and atomic physics. In recent years, a number of new applications have emerged in the area of quantum information theory. In this talk I will highlight two such applications. The first is the comparison between classical and quantum strategies to process information. Byproducts of this comparison are benchmarks that can be used to certify quantum advantages in realistic experiments, fundamental relations between quantum copy machines and precision measurements, and theoretical tools for security proofs in quantum cryptography. The second application is the simulation of unitary gates in quantum networks. Here the task is to simulate a given set of unitary gates using gates in another set, a general problem that includes as special cases the simulation of charge conjugate dynamics and the emulation of an unknown unitary gate. The problem turns out to have useful connections with the ultimate precision limits of quantum metrology.