Thin film metallic glasses (TFMGs) are characterized by a disordered atomic structure, leading to extraordinary mechanical properties such as large elastic limit (>2%), high hardness and yield strength (sy, 2 GPa), exceeding those of most traditional crystalline films. Moreover, the small volume of TFMGs hinder the nucleation and propagation of shear bands, leading also to a large plastic behavior (>10%) [1-2]. Nevertheless, the relationship between the atomic structure, mechanical properties and thermal stability is still not well understood, especially passing from a binary to a ternary composition. Furthermore, few studies are aimed at further improving the plasticity of these systems by building nano-architectures (i.e. multilayers or nanocomposites), capable of stopping/deviating shear bands propagation [3] which still remains an open challenge. In this context, various (Zr0.5Cu0.5)100-xAlx TFMGs (x = 0, 6, 8, 9, 12) and several multilayered structures made of Zr50Cu50/(Zr0.5Cu0.5)100-xAlx with different compositions and bilayer period (L= 50, 100, 200 nm) were deposited by magnetron sputtering and analyzed extensively. The structural and mechanical characterization was carried out by a large series of delicate experiments at Troom involving SEM/EDX, nanoindentation, tensile tests on polymeric substrates and in situ SEM micropillar compression. Furthermore, the thermal stability of ZrCuAl TFMGs was investigated in situ during devitrification phenomena by electrical resistivity measurements, optoacoustic techniques and synchrotron source-XRD. The addition of Al (up to 12 at.%) showed a moderate monotonic increase of elastic moduli (15%) and thermal stability of ZrCu-based TFMGs (the crystallization temperature increased from 420 to 510°C). Tensile test on polymeric substrate revealed a maximum of 2% in crack initiation strain for 9 at.% Al, where a peculiar cluster population (which lead to the maximum of glass forming ability) and a less covalent nature of Zr-Al bonds were theoretically predicted by ab initio molecular dynamics simulations. The mechanical properties of fully-amorphous ZrCu/ZrCuAl9 multilayers were investigated by micropillar compression, confirming the crucial role of L on sy and plasticity of the material. Especially, TFMGs with the smallest L (50 nm) demonstrated sy and elastic strain limit close to those of monolithic ZrCu (2000 MPa and 3%, respectively), while films with L of 100 nm showed lower sy (1000 MPa) with apparent plasticity due to blocking/deflection phenomena of shear bands propagation. Overall, our results will pave way to compositional and nanostructural design of novel TFMGs with large thermal stability and mechanical resistance, making them optimal candidates for a wide range of industrial applications.