  Entanglement is a fascinating feature of quantum mechanics and a key
ingredient in most quantum information processing tasks. Yet the generation of
entanglement is usually hampered by undesired dissipation owing to the
inevitable coupling of a system with its environment. Here, we report an
experiment on how to entangle two $^{13}$C nuclear spins via engineered
dissipation in a nitrogen-vacancy system. We utilize the electron spin as an
ancilla, and combine unitary processes together with optical pumping of the
ancilla to implement the engineered dissipation and deterministically produce
an entangled state of the two nuclear spins, independent of their initial
states. Our experiment demonstrates the power of engineered dissipation as a
tool for generation of multi-qubit entanglement in solid-state systems.
