This study reports the synthesis and comprehensive characterization of a new series of 1,2,4-triazolo[4,3-a] pyrimidin-5-(1 H )-one derivatives. These compounds were synthesized from 2-hydrazinopyrimidines via cyclization reactions. Density Functional Theory (DFT) calculations revealed the molecular structures, stability, and electronic properties of the derivatives. Computational studies revealed that the compounds exhibited...