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A series of bidentate pyridine‐functionalized palladium N‐heterocyclic carbene (Pd NHC) complexes with various wingtip substituents (R = methyl, phenyl and tert‐butyl) have been synthesized and evaluated for their potential biomedical applications as antimicrobials and antiproliferative drug candidates. The obtained Pd NHC complexes were applied in a standard broth microdilution assay for determination of their antimicrobial activities against thirteen strains of pathogenic microorganisms. In addition to that, cytotoxic activities of the Pd NHC complexes were also evaluated against three human cancer cell lines, namely breast (MCF‐7), colon (HCT116) and oral (H103) cancer cells, using a standard MTT assay. Upon coordination to palladium, the Pd NHC complexes show significant antimicrobial activities with minimum inhibitory concentrations in the micromolar range, and they are cytotoxic to the tested carcinomas with IC50 ranging from 13 to 38 μM. Evidences for influence of both wingtip substituents and optical isomerism on the biological activities of the complexes have been found.

Imidazolium salts have always been well recognized as the precursors to ionic liquids. Various studies have been extended to their biological properties, in which many have discovered interesting results. In this study, a series of pyridine‐functionalized (benz)imidazolium salts were synthesized using the conventional synthetic method, and microwave irradiation. The products were tested biologically against a list of microorganisms via broth microdilution assay and cancer cell lines using a standard MTT assay. Lead compound 4 e exhibited great antimicrobial properties with lowest MIC value of 3.91 μg/mL against Bacillus cereus, Bacillus subtilis, Staphylococcus aureus and Enterococcus faecalis. Remarkable anticancer properties of 3 f were shown with IC50 value as low as 0.71 μM against human colon cancer (HCT116). From our study, the MIC of 4 e and IC50 values of 3 f surpassed the potency of positive controls such as chloramphenicol (8.08–16.2 μg/mL) and cisplatin (10.78 μM) respectively. Additionally, the use of microwave irradiation has significantly reduced the reaction time from 5 days in a conventional setup, to a 3‐hour synthetic reaction in a microwave synthesizer.

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