The presence of mercury ion (Hg (II)) in the environment is a serious health concern. Therefore, it is essential to measure and monitor the levels of Hg (II) in the environment to safeguard public health. This study focuses on the synthesis of carbohydrazide-based Schiff bases (4–5) and exhibit a red-shift in absorption upon addition of Hg (II) ion, making them highly selective and sensitive in detecting Hg (II). The confirmation of the synthesized compounds was achieved using (1H and 13C) NMR spectroscopy and mass spectrometry. Additionally, the detection limits towards Hg (II) were determined to be 7.56 × 10-7 M and 1.42 × 10-6 M for compounds 4 and 5, respectively. The 1H NMR spectra provided evidence of interactions between compounds 4–5 and Hg (II) ion. The compounds 4 and 5 were evaluated for Bioactivity, Drug likeness parameters and Prediction of Activity Spectra (PASS) analysis to design a new molecule with a favorable pharmacological profile. Based on the PASS results, molecular docking studies of compounds 4 and 5 were performed with Cholesteryl Ester Transfer Protein (CETP) (PDB ID: 2OBD), revealing inhibitory activity. These findings suggest the potential of these compounds as candidates for antihyperlipidemic or cholesterol-lowering agents.