A variety of highly potent derivatives of 2-pyrazoline-5-one, including chromene-3-carbohydrazide 2, 2-thioxothiazole-5-carbohydrazide 3, 2-oxopyridine-3-carbonitriles (4–6), 3-aryl-2-cyanoacrylohydrazide (7, 8), and 3-amino-5-arylpyrazole-4-carbohydrazide (9, 10), were synthesized as pesticide agents using acetohydrazide 1, a versatile and easily obtainable compound. The compounds structures were entirely ascertained utilizing different spectroscopic methods, including Fourier-transform infrared (FTIR), nuclear magnetic resonance spectroscopy, and analysis of elements. In the laboratory, we assessed the impact of nine 2-pyrazoline-5-one derivatives on the fourth larval stage of the cotton leaf worm (Spodoptera littorals), Monacha obstructa, and Tetranychus urticae adults. We used abamectin as the reference compound. The LC₅₀ values of compound 3 for S. littorals, M. obstructa, and T. urticae are 0.90, 0 …