Molecular structures, spectroscopic properties (IR, H-1 NMR and C-13 NMR, UV-VIS), molecular electrostatic potential maps and some molecular properties (ionization energy, electron affinity, energy gap, hardness, electronegativity, electrophilicity index, static dipole moment and average linear polarizability) of three Schiff bases which are 2-((ethylamino)methyl)-6-methoxyphenol (HL1), 2-((ethylamino) methyl)-6-methylphenol (HL2) and 2-((ethylamino)methyl)-6-chlorophenol (HL3) were computed at B3LYP/6-31G(d) level in aqueous phase. The effects of methoxy, methyl and chloro substituents on Schiff bases were examined and it was found that the electron donating property of methyl and chlorine substituents was higher than the methoxy substituent. In order to investigate the antitumor activities of Schiff bases were docked against the breast cancer (MCF7) cell line. Molecular docking results were compared with antitumor standard 5-fluorouracil. Antitumor activity of HL2 and HL3 moleculewas found to be higher than HL1 againstMCF-7 cell line. In addition, in order to predict the antibacterial activities of Schiff bases were docked against the Mycobacterium tuberculosis (H37Rv) cell line. Docking resultswere compared with the antibacterial reference N-(salicylidene)-2-hydroxyaniline. Antibacterial activity of HL2 and HL3moleculeswas found to be higher than HL1. It is estimated that the binding of the electron donating group to the ortho position of the hydroxyl group in studied Schiff bases increases both antitumor and antibacterial activity. (C) 2020 Elsevier B.V. All rights reserved.