Four new Schiff-bases have been synthesized from the 1:2 M condensation of 4,5,6,7-tetrahydrobenzothiazole-2,6-diamine with 2-hydroxybenzaldehyde (SL3), 5-Bromo-2-hydroxybenzaldehyde (SL2), 2-hydroxy-3-methoxybenzaldehyde (SL3) and 2-hydroxy-1-naphthaldehyde (SL4) and charactrised by UV-Vis, FT-IR, H-1 NMR and mass spectroscopy. The crystal structures of SL1 and SL2 were determined by X-ray diffraction and the validity of gas-phase orT optimisations established by comparison with the diffraction data; by extension SL3 and SL4 were taken from DFT computations.

Molecular docking, circular dichroism and fluorescence quenching studies revealed one molecule of our Schiff-bases to bind to Human Serum Albumin (HSA). SL1 - SL4 are shown, by fluorescence quenching and circular dichroism, to present cytotoxic activity against the human breast-cancer (MCF-7) and the human hepatocellular liver-carcinoma (HepG2) cell lines in a concentration dependent manner: SL4 is the best in the series. (C) 2019 Elsevier B.V. All rights reserved.