Colloidal semiconductor nanomaterials (such as colloidal quantum dots or colloidal nanoplatelets) with controlled size, shape, and composition in a simple chemistry process are crucial in today’s optoelectronic devices. Fundamental problems with size, shape, structure (core/shell, core/crown/shell) and surface chemistry define the properties which are tailored for specific applications. Strong quantum confinement effect allows strong spontaneous emission for light emitting diodes; while engineering the confinement configuration (type II hetero-structure) can allows optical amplification at lower thresholds. Also by well adjusting the band structures with adjacent layers, colloidal semiconductor nanomaterials can show high performance as photovoltaics or photodetectors. To address these attractive issues, the symposium will cover the general topics from colloidal semiconductor nanoparticle synthesis, functionalization, characterizations, and applications in optoelectronics and photonics.