Abstract Industrialization and urbanization have now become major factors in damaging different segments of the environment. Synthesis of novel nanomaterials for the removal of dyes and free radicals from aqueous medium has become a challenge for the researchers. The present work describes formation of novel-franklinite (ZnFe₂O₄) nanoparticles (FNPs) which have been synthesized adopting economical route of green method using extracts of fresh and dried leaves of Coriandrum sativum. The fabricated NPs were characterized employing state of the art analytical techniques including UV-visible, FTIR, SEM and XRD. The nanocatalyst exhibited excellent catalytic properties for the degradation of eosin yellow up to 86 % in 22 min and 90 % in 16 min using zinc-ferrite NPs synthesized using dried and fresh leaves respectively. Antioxidant activity of ZnFe₂O₄ in terms of DPPH and ABTS free radicals scavenging was also determined. Nanoparticles synthesized using fresh leaves exhibited better antiradical potential in comparison to NPs synthesized dried leaves. Therefore, synthesis of FNPs with active features can be achieved using extract of fresh plant. Franklinite NPs can be used as promising photocatalyst for the degradation of organic pollutants and scavenging of free radicals.