This article reports the functionality of Paint/PMN-PT and Paint/PLZT composite films for use in pyroelectric infrared sensors and energy conversion devices. Smart Paint/Lead Magnesium Niobate-Lead Titanate (Paint/PMN-PT) and Paint/Lead Lanthanum Zirconate Titanate (Paint-PLZT) nanocomposite films have been fabricated by the conventional paint-brushing technique on copper substrate. The pyroelectric, piezoelectric, and dielectric properties of the composite films were measured for their use in uncooled infrared detectors and thermal energy conversion devices. The properties investigated include: dielectric constants (epsilon' and epsilon''); pyroelectric coefficient (p); and energy conversion performance. From the foregoing parameters, material’s figure-of-merits, for infrared detection and thermal energy conversion, were calculated. The results indicated that paint composite films are functional and figure-of-merits increase with increase in amount of PMN-PT and PLZT nanoparticles in paint matrix. Based on the preliminary results obtained, composite films are reasonably attractive for use in uncooled thermal sensing elements, and thermal energy conversion devices for low power applications, especially in applications where flexible and curved surface sensors are required. With these factors in consideration, a novel cantilever system is designed and examined for its performance. The highest voltage output and power accomplished were 65 mV and 1 nano-Watts, respectively for a particular structure with a broad frequency response operating in the 31 mode of Paint/PMN-PT based harvester. Efforts have been made to investigate the performance of nanocomposite films on copper substrate to mechanical vibrations and thermal variations as well. Thus, could be utilized for energy scavenging combining piezoelectric and pyroelectric effects.