Effect of basicity of porous metal-carboxylates, such as MIL-100(Al), Cu-3(BTC)(2)center dot(H2O)(3), UiO-66 and amino-modified UiO-66 materials (UiO-66-NH2) on their catalytic performance, was studied in the Knoevenagel condensation of benzaldehyde with malononitrile to 2-benzylidenemalononitrile. According to physicochemical studies, the strength of the basic sites for MIL-100(Al), Cu-3(BTC)(2)center dot(H2O)(3), UiO-66 was in the range of 830-839 kJ/mol, while the amount of basic sites decreased in the order MIL-100(Al) > Cu-3(BTC)(2)center dot(H2O)(3) > UiO-66. The insertion of NH2 groups into the UiO-66 framework led to an increase in the strength of basic sites from 839 to 867 kJ/mol. The catalytic activity of metal carboxylates correlated with the amount of basic sites and the strength of the interaction between metal and oxygen in the "M+n-O2- Lewis acid-base" pair, which was estimated from ionic covalent parameters. The activity of the UiO-66-NH2 materials was higher than that of UiO-66. (C) 2014 Elsevier Inc. All rights reserved.