Cognitive radio (CR) access is an alternative way of providing mobile services while achieving effective spectrum utilization. CR users can transmit data to one another in a cognitive radio network (CRN) as long as the primary user is prevented from being affected. In addition, a CR user needs to rendezvous with its correspondent user in order to transmit data in an ad hoc manner. This study considers secondary users (SUs) that have the ability to access dual-interface for simultaneously for rendezvous and data transmission. A fully distributed dual-interface channel hopping for a rendezvous scheme is proposed as is the associated data delivery method for ad hoc communication in CR networks. The proposed rendezvous and data transmission schemes consider the channel contention of multiple SUs and the occurrence of primary users (PUs) when accessing radio. Furthermore, relay operations are applied in the proposed schemes to reduce the average time of rendezvous and data transmission. Simulation results indicate that the proposed relay-based schemes achieve shorter rendezvous time and higher throughput (because of the relay-based mechanism) and facilitate superior performance in both balanced and unbalanced peer-to-peer transmission environments.