Ultrafast laser ablation synthesis techniques offer a rapid, straightforward, and eco-friendly approach for producing functional nanomaterials in comparison to alternative methods, like colloidal chemistry. While previous studies have primarily focused on synthesizing nanomaterials and characterizing their structures and properties, there remains a significant gap in our understanding of the underlying physical processes that occur during ablation and material formation under extreme conditions. In particular, obtaining experimental data on transient parameters, such as temperature and pressure, during ablation possesses significant challenges. As a result, there is a growing interest in ongoing research efforts aimed at unravelling the formation mechanisms of a variety of functional nanomaterials and exploring their potential applications. Femtosecond lasers offer a significant advantage in their capacity to generate nanostructures through a limitless array of solid targets and liquid mediums in a ‘green’ way. This chapter outlines the proficiency of femtosecond laser ablation as a fundamental technique for producing nanoscale assemblies comprising various functional materials, which exhibit intriguing physical and chemical properties.