Herein we present the synthesis, and biological evaluation of new Schiffbases incorporating (2-hydroxy-5-methylbenzaldehyde sulfisoxazole (S2M-S1) and 2-hydroxy-5-methylbenzaldehyde sulfamethoxazole (S1M-S1) derived from sulfisoxazole (S2)/sulfamethoxazole (S1) and substituted salicylaldehyde and their Pd (II), Cu(II) complexes. The synthesized compounds were characterized by FT-IR, H-1-C-13 NMR, LC-MS, magnetic susceptibility and conductivity measurements. The molecular structure of S2M-S1 was also determined by the single crystal X-ray diffraction technique and was found to crystallize in the monoclinic, space group P1 21/n 1. We investigated the effects of molecules on human carbonic anhydrase isoenzyme II (hCAII). Cu(S2M-S1)(2), Pb(S2M-S1)(2), Pb(S1M-S1)(2), and Cu(S1M-S1)(2), exhibited inhibitory effects with 10, 20, 42 and 67 mu M IC50 value, respectively. Also, molecular Docking studies performed and anticancer activities of newly synthesized compounds were evaluated against three human cancer cell lines with the sulfonamide B test. S2M-S1, S1M-S1 compounds and their Cu (II) complexes exhibited promising cytotoxic activity against all cell lines. IC50 values for breast (MCF7) cells are 40 mu M for S2M-S1, S1M-S1 compounds and their Cu (II) complexes. (C) 2020 Elsevier B.V. All rights reserved.