The prevalence of both antimicrobial resistance (AMR) and neglected tropical diseases are on the rise, with the parasitic ailment leishmaniasis being no exception. Leishmania's locality in 90+ tropical/sub-tropical low socioeconomic countries and increased cases of established drug resistance, makes the design and characterisation of new potentially low-cost drug candidates a high priority.1, 2 Previous studies by Andrews et al found that the organometallic dimethyl gallium complexes of the medically active class of halide substituted 8-quinolinols had potent activity toward the parasites while maintaining a high degree of selective toxicity.3 The hydrolytically stability of the Ga-C bond is advantageous as it is thought to prevent the facile scavenging and exchange of Ga (III) by Fe (III) containing proteins such as transferrin.4 Parasites and bacteria often rely on exogenous source of iron and therefore scavenge these from their hosts. Their inability to distinguish between Ga (III) and Fe (III) is thought to lead to preferential uptake of Ga (III) leading to metabolic distress and cellular apoptosis due to the inability of Ga (III) to undergo homeostatic biological redox.5 As the previous dimethyl complexes exhibited a high degree of antimicrobial activity, modulation of the R group was next explored to investigate whether changes in alkyl chain length and complexity would lead to changes in antimicrobial activity and lipophilicity. ICP-MS of the gallium content in cell media doped with fetal bovine serum also provided insights into the rate of exchange into proteins of organometallic Ga (III) complexes versus inorganic Ga (III) complexes, in low iron environments, supporting hypotheses for the increased activity of organometallic versus inorganic Ga (III), whilst simulating the hosts iron content in vivo. Herein, we present the synthesis, characterisation and biological application of a series of di-alkyl gallium 8-quinolinols toward Klebsiella pneumoniae and three species of Leishmania.