As a bottom-up approach, stable elemental and mixed nanoclusters may serve as building blocks for nanomaterials. Boron, the prototypical electron-deficient element in the periodic table, is well-known for multicenter bonds. Boron forms various kinds of important and interesting nanoclusters, from the planar B_n-/0(n=3-36) clusters, tubular B_n⁺(n=16-30) clusters, to the cage-like borospherenes (such as B₃₉- and B40^-/0). Much more remains to be explored in the medium-sized range.Using the joint theoretical and experimental approach, we are currently investigating the medium-sized boron-based nanoclusters, focusing on their geometric and electronic structures, bonding characters, growth mechanisms, and possible applications. Specifically, the theoretical methods involve the global-minima searches, density functional theory (DFT), and accurate ab initio calculations, whereas the experimental techniques include the infrared photodissociation spectroscopy (IR-PDS), photoelectron spectroscopy (PES), arc-discharge, and laser-sputtering.