<p>Infilled frames are widely used in framed building systems due to their enhanced load-bearing capabilities. However, the interface material between the infill and the frame significantly affects the structural response, a factor that remains inadequately explored in existing studies. This research addresses the scientific problem of optimizing the interface material to improve the structural performance of infilled frames under loading conditions. The novelty of this study lies in investigating the influence of unconventional and composite interface materials specifically Cement Mortar, Cork, Rubber, and their combinations on the structural behavior of infilled frames. A total of seven infilled frame configurations were modelled and analysed using finite element simulations in ABAQUS. Key performance indicators such as first crack load, ultimate load, stiffness, and displacement were examined to assess the impact of each interface type. The simulations results demonstrated that all infilled frames exhibited improved structural behaviour compared to the bare frame. The use of rubber as an interface material resulted in superior stiffness, yielding a maximum ultimate load of 67.2 kN, surpassing that of the other frames. The rubber interface demonstrated first crack and ultimate loads that were 226.21% and 226.37% greater than those of the bare frame model, respectively. This study concluded that rubber interface materials possess exceptional damping properties, making them ideal for scenarios involving dynamic loading.</p>