Antimicrobial resistance poses a significant threat to global health and is exacerbated by the propensity for pathogenic species to form biofilms. Biofilms are communities of homo or heterogenous microorganisms encased in an extracellular polymeric matrix, impeding antibiotic diffusion to susceptible bacterial cells. Additionally, there is a dearth of antibiotics in the clinical pipeline, resulting in an urgent need for novel antibacterial agents, including ones to target and eradicate biofilms. This project aimed to address the above through the design and synthesis of dual-acting antimicrobials known as ‘hybrids’. These hybrids combine separate moieties to provide antibacterial and antibiofilm activity. Our approach to hybrid development involves the installation of an azide to an antibiotic and an alkyne to an antibiofilm agent, to be linked using copper-catalysed azide-alkyne cycloaddition chemistry. Here, we report on our ammonium and phosphonium-based hybrids, more than 20 spanning six antibiotic classes, designed to inhibit biofilm activity and retain anti-planktonic activity. Compounds were evaluated against Gram-positive and Gram-negative strains, including multi-drug-resistant isolates, in planktonic and biofilm inhibition assays. Cytotoxicity was assessed using human embryonic kidney cells, and haemolysis was measured against healthy human red blood cells. Conjugates displayed significant variation compared to parent antibiotics and alkyne ‘onium’ intermediates. One macrolide hybrid, ROX-PCM5, exhibited enhanced activity against planktonic and biofilm populations, including multidrug-resistant species, and no cytotoxicity at tested concentrations (>64 µg/mL) To assess synergistic or additive effects, unconjugated moieties were combined at a 1:1 molar ratio; no additive effect was observed. The success of ROX-PCM5 unlocks a new area of research, with current efforts exploring similar modifications to another antibiotic from this class. With further success, we may be able to restock the antibiotic drug development pipeline.