Abstract <p>Green synthesis is an emerging technique for developing nanocomposites for water treatment applications. Factors such as extract type, precursor ratio, and calcination temperature can significantly influence the efficiency of the nanocomposites. Calcination temperature is an important factor used to control their properties. In this study, we synthesized ZnFe₂O₄@ZnO nanocomposites using chrysanthemum flower extract at three different calcination temperatures (400°C, 500°C, 600°C). The morphological, optical, magnetic, and electrical properties of the prepared nanocomposites were studied in detail. The results reveal that the crystallite size of the proposed nanomaterial increases with the increase in calcination temperature. Optical analysis suggests that the bandgap energy (Eg) increases with the calcination temperature. Additionally, the photocatalytic degradation of methylene blue (MB) and rhodamine B (RhB) was performed. The experiment shows that the sample calcined at 400°C exhibits maximum efficiency, with removal of 93.7% of MB and 90% of RhB dye from water. The study suggests that the photocatalytic efficiency of the proposed material is greatly influenced by calcination temperature.</p> Graphical Abstract <p></p>