Acidizing is the important process used in petroleum industry for oil well stimulation. Here, we are exploring the green synthesis of 4,4'-((4-methoxyphenyl)methylene)bis(3-methyl-1-phenyl-1H-pyrazol-5-ol) (PZ-1) and 4,4'-((4-nitrophenyl)methylene)bis(3-methyl-1-phenyl-1H-pyrazol-5-ol) (PZ-2) under ultrasonic irradiation and its potential application for N80 steel corrosion mitigation in 15% HCl. The corrosion inhibition investigation was performed by open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), linear polarization (LPR), potentiodynamic polarization (PDP), electrochemical frequency modulation (EFM), and electrochemical frequency modulation trend (EFMT), weight loss, scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), density functional theory (DFT) and molecular dynamics (MD). The EIS and PDP results suggests an increased impedance in presence of PZs and mixed nature of inhibitor action respectively. The protection efficiency (eta%) are 98.4% (PZ-1) and 94.3% (PZ-2). The results of EFMT provides the average decrease in corrosion rate and corrosion current density (i(corr)).The surface analysis suggests a protective layer of PZs. DFT analysis reveals that PZ-1 with lower value of Delta E acts as a better inhibitor compared to PZ-2. MD study supports a stronger binding and interaction ability of PZ-1 than PZ-2. (C) 2020 Elsevier B.V. All rights reserved.