<p>In this study, a hydrazine-containing Schiff base (ScB) and its metal complexes with five different metals—Co (ScB-Co), Cu (ScB-Cu), Pb (ScB-Pb), Mn (ScB-Mn), and Zn (ScB-Zn)-were synthesized and subsequently characterized both structurally and thermally. The ScB was synthesized via an elimination reaction between vanillin and phenylhydrazine in ethanol. Hexadentate homometallic complexes (HMCs) were then obtained by reacting the ScB with five different metal salts in tetrahydrofuran. The structural architecture of the synthesized ScB and its HMCs was elucidated using Fourier Transform Infrared (FT-IR) spectroscopy, as well as proton (¹H) and carbon (¹³C) Nuclear Magnetic Resonance (NMR) spectroscopy. Optical, thermal, and surface characterizations of the structurally confirmed ScB and HMCs were performed using UV-Visible spectroscopy (UV-Vis), thermogravimetric and differential thermogravimetric analyses (TG-DTG), and scanning electron microscopy (SEM), respectively. According to thermogravimetric analysis, the char yield of ScB was 28.2%, while the char yields of its metal complexes—ScB-Co, ScB-Cu, ScB-Pb, ScB-Zn, and ScB-Mn—were 5.4%, 27%, 16%, 19%, and 7.1%, respectively. These results indicate that the incorporation of metal ions into the structure reduced its thermal stability, as evidenced by the decreased residue amounts at 1000&#xa0;°C.</p> Graphical Abstract <p></p>