Traditional Mesh based Networks-on-Chips, are inherently slow due to hop-by-hop packet forwarding. The addition of Express Channels has emerged as a viable solution to reduce packet latency. However, there is a lack of application mapping methods, which can take into account the nature of the Express Channels. In this paper a constructive heuristic based approach has been proposed for application mapping onto an Express Channel based Network-on-Chip. The simulation results indicate that the proposed method significantly reduces the average packet delay compared to the existing methods even in the presence of high network load.