Chalcones are a group of plant-derived polyphenolic compounds possessing a wide variety of biological activities. The aim of this study was to synthesize 2,6-dihydroxy-4-isopentenyloxychalcone (1), a chalcone found in plants belonging to the genera Helichrysum, Pleiotaxix and Metalasia, and evaluate its antimicrobial effects against major oral pathogens as well as its anti-inflammatory properties. Compound 1 was synthesized using a simple two-step procedure. Among the seven pathogens tested, Porphyromonas gingivalis and Prevotella intermedia were the most susceptible to inhibition by 1. This chalcone also attenuated the secretion of interleukin-8 and chemokine (C-C motif) ligand 5 (CCL5) by lipopolysaccharide (LPS)-stimulated oral epithelial cells as well as the secretion of matrix metalloproteinase 2 (MMP-2) by LPS-stimulated gingival fibroblasts. In conclusion, our study showed that 1 exerts a dual effect by acting on both oral pathogens and the host inflammatory response and thus represents a molecule of interest for periodontal infections.