FIGURE S1 FT-IR of 5-(3-fluorophenylazo)salicylaldehyde (3-FAS)

Figure S2 FT-IR of (a) L², (b) [Ni₂(L²-H)(OAc)₃(H₂O)], (c) L⁴, (d) [Ni(L⁴-H)(OAc)(H₂O)]

Figure S3 ¹H NMR spectra of (a) L³, (b) [Ni(L³-H)₂].4H₂O

Figure S4 ¹H NMR (DMSO-d₆) spectrum of L⁴

Figure S5 ¹H NMR (DMSO-d₆ + D₂O) spectrum of L⁴

Figure S6 ¹³C NMR (DMSO-d₆) spectrum of L³

Figure S7 ¹³C NMR (DMSO-d₆) spectrum of L⁴

Figure S8 Mass spectrum of L³

Figure S9 Mass spectrum of L⁴

Figure S10 Mass spectrum of complex (1)

Figure S11 Mass spectrum of complex (2)

Figure S12 Mass spectrum of complex (3)

Figure S13 Mass spectrum of complex (4)

Figure S14 Optimized structures of (a) L¹, (b) L² using DFT-B3LYP/6-31G method

Figure S15 Optimized structures of (a) L³ and (b) L⁴ using DFT-B3LYP/6-31G method

Figure S16 Optimized structure of [Ni₂(L¹-H)(OAc)₃(H₂O)] complex (1)

Figure S17 Optimized structure of [Ni(L³-H)₂] complex (3)

Figure S18 LUMO and HOMO of (a) L¹ and (b) L²

Figure S19 LUMO and HOMO of (a) L³ and (b) L⁴

Figure S20 LUMO and HOMO [Ni₂(L²-H)(OAC)₃(H₂O)] complex (2)

Figure S21 Molecular electrostatic potential map of L¹

Figure S22 Molecular electrostatic potential map of L³

Figure S23 Molecular electrostatic potential map of L⁴

Figure S24 Binding features (a) surface maps (b) of the best docked poses of the synthesized ligands (L¹, L² and L³) against breast cancer protein 3s7s

Figure S25 Binding features (a) surface maps (b) of the best docked poses of the synthesized complexes (1) and (2) against breast cancer protein 3s7s

Figure S26 Binding features (a) surface maps (b) of the best docked poses of the synthesized complex (3) against breast cancer protein 3s7s

Figure S27 The inhibitory dose response curves of some selected ligands against HepG2

Figure S28 The inhibitory dose response curves of some selected complexes against HepG2

Figure S29 The inhibitory dose response curves of some selected ligands against HCT-116

Figure S30 The inhibitory dose response curves of some selected complexes against HCT-116

Figure S31 The inhibitory dose response curves of some selected complexes against normal oral epithelial cell line (OEC)

Table S1. IR spectra (4,000–400 cm⁻¹) of L¹-L⁴ ligands and their Ni (II) complexes.

Table S2. Selected bond lengths (Å) and bond angles of L², L⁴, and their complexes