A novel isatin-thiazole-coumarin hybrid and three isatin-hydantoin hybrids were synthesized and assessed for their α-glucosidase and anticholinesterase inhibitory activities. Moreover, their anticancer properties have been observed against the breast cancer cell lines MCF-7 and MDA-MB-231. The coumarin-containing hybrid exhibited the most potent biological activity across all assays. These hybrids demonstrated significant enzyme inhibition and cytotoxicity, highlighting their potential as multifunctional therapeutic agents for metabolic disorders and breast cancer treatment. This study underscores the value of isatin-based hybrid scaffolds in drug discovery. The synthesized isatin coumarin hybrid 5 demonstrated promising cytotoxic activity against both MCF-7 and MDA-MB-231 breast cancer cell lines, with IC50 values of 10.85 μg mL−1 and 14.45 μg mL−1, respectively. The biological evaluation showed that compound 5 had impressive multi-target activity. It displayed strong anticholinesterase inhibition (IC50 = 0.0998 μg mL−1), effective α-glucosidase inhibition (IC50 = 112 μM), and notable anti-MRSA activity (MIC = 1.3 μg mL−1). Molecular docking backed up these findings by showing good binding interactions with the active sites of the target enzymes. The results indicate that compound 5 is a promising candidate for developing multifunctional agents. It could have potential uses in managing neurodegenerative, metabolic, and infectious diseases.