AbstractA series of gold(I) pioneer complexes bearing N‐heterocyclic carbenes and steroid derivatives (ethynylestradiol and ethisterone) with the generic formula [Au(R2‐imidazol‐2‐ylidene)(steroid)] (where R=CH3 or CH2CH2OCH3) were synthesized, and the X‐ray structure of a rare of gold(I)–estradiol derivative is discussed. Toxicity studies reveal notable antibacterial activity of the gold‐based compounds, which is significantly increased in vivo by the presence of the estradiol unit. Toxicity profiling was estimated in vitro versus Gram‐positive (Staphylococcus aureus) and Gram‐negative (Escherichia coli) bacteria, and in vivo on Galleria mellonella larvae against E. coli.