Purpose: The cimemoxin derivatives and their biological importance in antioxidant, antibacterial, and cytotoxic activities were the main focus of this study. By using a one-step reaction and green chemistry method, this study was able to synthesise derivatives of cimemoxin-related Mannich base compounds. Methods: Green chemistry can be used to prepare new, one-pot syntheses of cimemoxin derivatives (1a-i) Mannich base derivatives. FTIR, mass spectrometry, elemental analysis, and 1H and 13C NMR were used to analyse the newly synthesised compounds. The cytotoxic, antibacterial, and antioxidant activities of synthesized compounds (1a-i) were investigated. To test all synthesised compounds (1a–i) for cytotoxicity against normal Vero cell lines and MCF-7, the antioxidant activities were studied using DPPH, NO, H2O2, and ABTS•+ assays. The synthesised compounds were screened for anti-tyrosinase and antibacterial activities. Highly active compounds were investigated using molecular docking studies. Results: The compound 1h showed considerable activity in H2O2 (IC50: 13.79 µg/mL) and DPPH-scavenging was significantly active (IC50: 19.62 µg/mL) compared to the standard BHT (IC50: 27.16 and 33.88 µg/mL). Compound 1f was more effective than trolox (85.28 %) against ABTS and AAPH antioxidants. The most potent inhibitory activity was observed for compound 1h (IC50 = 15.16 µg/mL) which was more potent than kojic acid (IC50 = 17.79 ± 0.95 µg/mL). All synthetic substances were tested for their cytotoxic potential. Compound 1f (IC50 = 0.12 µg/mL) was extremely active compared to doxorubicin (IC50 = 0.74 µg/ml) and other compounds were lowly active compared to the MCF-7 cell line. In terms of anti-tyrosinase activity, compound 1h was highly active compared with the standard, and compound 1d was highly active against K. pneumonia. Conclusion: In this study, strong antioxidant, antibacterial, and cytotoxic activities were reported for all the compounds. In molecular docking studies, compounds 1d and 1h had higher binding affinities than the other compounds. Compounds 1d and 1h performed well in all tests. Additionally, this investigation successfully identified a number of intriguing compounds with cytotoxic and antioxidant properties.