Purpose <p>This work demonstrates the extraction of phytochemicals from Water hyacinth stems- considered as an agro-waste product, through diverse solvents (conventional solvents as well as Ionic liquid as solvent) to substantiate solvent specific extraction of phytochemicals.</p> Methods <p>Phytochemicals of water hyacinth stems were qualitatively profiled via spectrophotometric methods. Further, quantitative analysis of extracts was performed, as per standard protocols, for their polyphenolic content. Additionally, antioxidant capacity of the extracts was evaluated via three different assays: 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay, 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation decolourization assay and Cu²⁺ reducing antioxidant capacity (CUPRAC) method. Further, antibacterial activity was assessed against two most common foodborne pathogens: <i>Escherichia coli</i> and <i>Staphylococcus aureus</i>.</p> Results <p>Qualitative analysis of extracts exhibited a variety of phytochemicals such as alkaloids, phenols, sterols, N- &amp; S- compounds etc. Remarkably, ionic liquid extract had a similar phytochemical composition to that of conventional solvent extracts signifying effective extraction capability, except for acidified methanolic extract which possessed a unique bioactive compositional matrix altogether. Ionic liquid extract displayed highest yield ((6.67 ± 0.11) %), and a high polyphenolic content second only to acidified methanol extract. Similar to polyphenol quantification, ionic liquid extract also demonstrated high antioxidant capacity following acidified methanolic extract. On the other hand, the presence of a unique phytochemical matrix as well as high polyphenolic content of acidified methanol extract are reasonable contributors to its high antioxidant capacity (1223.15 ± 6.80 µmol/ g &amp; 597.64 ± 4.25 µmol/ g in ABTS &amp; CUPRAC assays, respectively) as well as exclusive antibacterial activity. Interestingly, acidified methanol extract demonstrated equal bactericidal efficacy (0.08&#xa0;mg/mL) against both <i>E. coli</i> and <i>S. aureus</i>.</p> Conclusion <p>This paper reports the first evidence of the application of ionic liquids as an efficient extracting solvent for water hyacinth stems that highlights solvent-specific extraction of phytochemicals responsible for imparting functional properties.</p> Graphical Abstract <p></p>