The accelerating spread of antimicrobial resistance has intensified the search for novel small-molecule scaffolds that can deliver potent, broad-spectrum activity while retaining drug-like properties. Five-membered nitrogen/oxygen heterocycles—particularly triazoles (1,2,3- and 1,2,4-) and oxadiazoles (1,2,4- and 1,3,4-)—have emerged as privileged motifs in antimicrobial lead discovery. This short review summarizes the structural features, common synthetic approaches, structure–activity relationships (SAR), and representative antimicrobial profiles of triazole- and oxadiazole-based compounds including hybrid chemotypes that combine both rings to achieve synergistic effects. We highlight key substitution patterns, linker choices, and physicochemical trends associated with antibacterial and antifungal potency, and outline design principles to address resistance and optimize pharmacokinetics.