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<div><p>The objective of this study was to develop pyrazolidine-3,5-dione derivatives with potential as environmentally friendly pesticides for pest control, specifically focusing on their efficacy as larvicidal agents. A novel one-pot synthesis of multicomponent pyrazolidine-3,5-dione derivatives (<b>1a-m</b>) was accomplished via the grindstone method using Cu(II)tyrosinase enzyme as a catalyst under mild reaction conditions, yielding 84%–96%. The synthesised derivatives (<b>1a-m</b>) were characterized using various spectroscopic methods (mass spectrometry, elemental analysis, FT-IR, and <sup>1</sup>H and <sup>13</sup>C NMR). NMR characterisation using DMSO-<i>d</i><sub>6</sub> as a solvent. The larvicidal and antifeedant activities of the synthesised compounds were screened and <i>in silico</i> computational studies were performed. The larvicidal activity against <i>Culex quinquefasciatus</i> and antifeedant activity against <i>Oreochromis mossambicus</i> were evaluated. Among the synthesised compounds, compound <b>1c</b> demonstrated superior efficacy (LD<sub>50</sub>: 9.7 μg/mL) against <i>C</i>. <i>quinquefasciatus</i> compared to permethrin (LD<sub>50</sub>: 17.1 μg/mL). Regarding antifeedant activity, compounds <b>1a</b>, <b>1e</b>, <b>1f</b>, <b>1j</b>, and <b>1k</b> exhibited 100% mortality at 100 μg/mL. Molecular docking analysis was performed to assess the binding capacity of a mosquito odorant-binding protein (3OGN) from <i>Culex quinquefasciatus</i> to compound <b>1c</b>. The results revealed that compound <b>1c</b> had a docking score of -10.4 kcal/mol, surpassing that of standard permethrin (-9.5 kcal/mol). Furthermore, DFT calculations were conducted to acquire theoretical data aligned with the experimental FT-IR results. According to experimental research, compound <b>1c</b> demonstrates promising larvicidal activity against mosquito larvae of <i>C</i>. <i>quinquefasciatus</i>.</p></div>