  We establish two complementarity relations for the relative entropy of
coherence in quantum information processing, i.e., quantum dense coding and
teleportation. We first give an uncertaintylike expression relating local
quantum coherence to the capacity of optimal dense coding for bipartite system.
The relation can also be applied to the case of dense coding by using unital
memoryless noisy quantum channels. Further, the relation between local quantum
coherence and teleportation fidelity for two-qubit system is given.
