Nanocrystals as small-scale building blocks are significant elements of low-dimensional materials, which have attracted more and more interests in exploration of novel physical and chemical behaviors. Preparation of monodisperse and size-/shape-tunable nanocrystals enables possibilities of physically determining various collective properties of nanoscale materials (such as the structural, electronic, magnetic, thermoelectric and optical properties), offering many opportunities of discovering novel phenomena, improving certain properties, building-up nano-devices and proving new concepts. Among various processing techniques, high-temperature organic solution approach is one of the most powerful strategies to generate high-quality, monodisperse and size-/morphology- controlled nanocrystals with high-crystallinity. This talk will focus on the details of this wet-chemical preparation and manipulation techniques, demonstrated by using several “model” materials (such as In2O3 nanocrystlas) in correlation with their improved properties.