Background: Synthesize new complexes of Ag(I) to enhance efficacy or stability and also, pharmacological activities on the operation of pyrazolone’s biological properties. Results: Efficient and high yielding pathways starting from the versatile and readily available 3-methyl-1-phenyl- 5-pyrazolone by Knoevenagel condensation of a sequence of 4-arylidene-3-methyl-1-phenyl-5-pyrazolone derivatives (2a-c) have been formed by the reaction of various substituted aromatic aldehydes Used as ligands to synthesize Ag(I) chelates. Synthesized compounds and their complexes have been characterized by elemental analysis, magnetic and spectroscopic methods (IR, 13C, 1HNMR, mass) and thermal analysis. The spectrophotometric determinations suggest distorted octaedral geometry for all complexes. Both ligands and their metal complexes have also been tested for their antibacterial and antifungal efficacy. Conclusions: Newly synthesized compounds have shown potent antimicrobial activity. The results showed that the complex ’s high activity was higher than its free ligands, and that Ag(I)-L3 had the highest activity. Keywords: Pyrazolones, Ag(i) complexes, Knoevenagel condensation, Antimicrobial activity