Flexible hybrid electronics (FHE) is an emerging field which combines printed electronics with flexible and/or discrete electronic components into a fully flexible electronic system. Applications for FHE’s include asset monitoring of time critical inventory (e.g. pharmaceuticals, produce, biological samples); as well as environmental and human performance monitoring. A significant challenge in FHE technology is development of attachment strategies for connecting flexible silicon integrated circuits to flexible printed circuit boards (PCB). State of the art technology typically involves microdispense printing of silver epoxies to connect IC leads to the PCB, but this approach limits reliability and the minimum feature size of the IC pins. In this study we investigate an emerging approach for IC attachment, anisotropic conductive adhesives (ACA). Using a custom hot press we investigate the effects of heat on pressure on the reliability and performance of ACA materials. Our results suggest 50 psi at 130 °C as the optimum attachment condition for mechanical test die. Applying these conditions to American Semiconductor flexible operational amplifier IC’s we further investigate the reliability of the ACA under realistic operational conditions. We find ACA material quickly fails, likely limited by power dissipation and the highly thermally insulating materials using in FHE technology.