Abstract
<title>Abstract</title> <p> A molecular hybridization strategy was used to design and synthesize two series of novel 1,2,3-triazole-linked isatin and 5-fluoroisatin hybrids incorporating the biologically important indoline-2,3-dione and 1,2,3-triazole pharmacophores into a single scaffold. The target compounds were efficiently prepared via Cu(I)-catalyzed click chemistry using a flexible 5-chloropent-1-yne linker to enhance pharmacophore orientation. All synthesized derivatives were fully characterized and evaluated <italic>in vitro</italic> against the lung (A549) and breast (MCF-7) cancer cell lines. Among them, compound <bold>4g</bold> (3-NO₂) showed significant cytotoxic activity with IC₅₀ values of 11.35 ± 1.16 µg/mL (A549) and 14.56 ± 0.34 µg/mL (A549) as compared to methotrexate. At IC₅₀, morphological analysis showed typical signs of apoptosis such as cell shrinkage and membrane blebbing. The compounds also exhibited selective antibacterial activity against Gram-positive bacteria, with compound <bold>4a</bold> being highly active against the Staphylococcal Infection (18.0 ± 1.30 mm). Structure–activity relationship analysis has revealed that electron-withdrawing substituents as well as 5-fluoro substitution on the indoline-2,3-dione core gave a significant increase in the biological activity. The molecular docking and molecular dynamics simulations showed good binding in the active site of the EGFR, supporting the experimental results, and the favorable ADMET profile suggests that these hybrids are promising lead candidates for the development of anticancer and antibacterial agents. </p>