The possibility of using ionic polymer metal composites (IPMCs) in engineering applications has been, in the last two decades, both a mandatory and a tantalising prospect that has raised the interest in this novel technology. A perusal of the huge literature on IPMC applications published so far would reveal that there has been a constant contribution to IPMC-based applications that, along with contributions to IPMC production technology and modelling, represent three research fields that influence each other. This chapter focuses on the possibility of using IPMCs for the realisation of smart devices. More specifically, the capability of an IPMC membrane to work, in a reversible way, both as an actuator and as a sensor has had the effect of producing two main directions in the development of applications and it is possible to classify them according to their exploitation of IPMC sensing capabilities or IPMC use as actuators. Finally, applications are described in which IPMC transducers, used both as sensors and actuators, cooperate to realise smart devices.