(2E)-1-(Biphenyl-4-yl)-3-(4-nitrophenyl)prop-2-en-1-one (BNO), (2E)-3-(4-aminophenyl)-1-(biphenyl-4-yl) prop-2-en-1-one (BNH), and (2E)-1-(biphenyl-4-yl)-3-(4-hydroxyphenyl)prop-2-en-1-one (BOH) were synthesized and characterized by FT-NMR, FT-IR, and elemental analysis. The synthesized compounds were investigated for corrosion inhibition of mild steel in hydrochloric acid medium by means of weight loss measurements, polarization studies, electrochemical impedance spectra, and the adsorption isotherm. Among the biphenyl chalcone derivatives, BOH showed higher efficiency against corrosion of mild steel. All the inhibitors were predominantly found to be cathodic in nature. The thermodynamic parameter values of the free energy of adsorption (Gads) reveals that inhibitor was adsorbed on the mild steel surface and the adsorption mechanism of inhibition was supported by FT-IR, surface analysis (SEM-EDS), and adsorption isotherms.