Solution-processed semiconducting transition metal dichalcogenides commonly serve as quintessential 2D substrates and templates to develop hybrid structures with novel and/or enhanced properties and performance. However, the effects and control of their ubiquitous and abundant structural defects are still poorly explored and understood. Here, exploiting their highly reactive and defective edges, an unprecedented strategy is introduced for their toposelective functionalization with noble metal nanoparticles through galvanic displacement. Selectively edge-decorated transition metal dichalcogenides nanosheets are successfully produced with gold, palladium, or platinum nanoparticles, showing tunable loading and size. As proof of concept, the hybrid systems are tested for optical and photothermal sensing, as well as electrocatalysis and electronics, demonstrating their enhanced functionality and broad applicability. These findings pave the way for the versatile production of mixed-dimensional multifunctional materials, achieved by harnessing the defective nature of solution-processed transition metal dichalcogenides via molecular chemistry approaches.