This paper report on the development and field trial of a dual-band and dual-use system based on a single photonics-based transceiver and a single radiating element, able to simultaneously carry out radar and communication functionalities. The coexistence of the two operations does not introduce any penalty on the system performance. The innovative sharing of both transceiver and antenna element allows for a reduction in terms of cost and Size Weight and Power consumption. The dual-use radar-communication system has been demonstrated in a outdoor field trial combining a radar experiment in S-band and C-band OFDM (Orthogonal Frequency Division Multiplexing) communication.