Abstract: Compositions, systems, and methods for producing nanoalloys and/or nanocomposites using tandem laser ablation synthesis in solution-galvanic replacement reaction (LASiS-GRR) are disclosed. The method may include disposing a first metal composition within a reaction cell, adding a quantity of a second metal composition into the reaction cell, ablating, with a laser, the first metal composition disposed in the quantity of the second metal composition within the reaction cell, and tuning one or more reaction parameter and/or one or more functional parameter during the tandem LASiS-GRR in order to tailor at least one characteristic of the metal nanoalloy and/or the metal nanocomposite.