The first-principles calculations have been performed to investigate the ground-state properties of monoperiodic boron nitride (BN), TiO 2 , and SrTiO 3 single-walled nanotubes (SW NTs) containing extrinsic point defects. The hybrid exchangecorrelation functionals PBE, B3LYP, and B3PW within the framework of density functional theory (DFT) have been applied for large-scale ab initio calculations on NTs with the following substitutional impurities: Al B , P N , Ga B , As N , In B , and Sb N in the BN NT, as well as C O , N O , S O , and Fe Ti in the TiO 2 and SrTiO 3 NTs, respectively. The variations in formation energies obtained for equilibrium defective nanostructures allow us to predict the most stable compositions, irrespective of the changes in growth conditions. The changes in the electronic structure are analyzed to show the extent of localization of the midgap states induced by defects. Finally, the electronic charge redistribution was calculated in order to explore the intermolecular properties, which show how the reactivity of the NTs under study was affected by doping and orbital hybridization.