Colloidal nanomaterial inks provide a versatile platform for fabricating functional materials and devices across electronics, energy, and emerging bioapplications. Central to their performance is interfacial chemistry, which governs nanocrystal stability, assembly, and coupling across multiple length scales, from solution to solid-state films. This symposium will highlight recent advances in understanding and controlling interfaces in colloidal quantum dot and nanomaterial systems, including ligand design, surface reactivity, and interparticle interactions. Particular emphasis will be placed on elucidating how interfacial phenomena influence ink formulation, processing pathways, and the resulting structural and functional properties of assembled materials. Contributions addressing synthesis, in situ and in operando characterisation, and data-driven or automated approaches to reproducibility and scale-up are encouraged. By bridging fundamental insights with application-driven design, the symposium aims to connect interfacial chemistry to device performance in next-generation technologies, including optoelectronics, energy conversion, and sensing applications.