A glassy carbon electrode (GCE) has been modified by an in situ electrochemical reduction of an aryldiazonium salt generated from the reaction of 4‐aminobenzoic acid and sodium nitrite in acidic ethanolic solution. The as‐prepared phenyl carboxylic acid‐modified glassy carbon electrode has been, for the first time, used for the electrochemical determination of dopamine. Under optimal experimental parameters, outstanding electrocatalytic activity, high sensitivity at a LOD of 5.6×10
−9
m
, and broad linearity of 0.1 to 1000 μ
m
were obtained. The crafted electrochemical platform demonstrated excellent stability, specificity, and anti‐interference capability towards the sensing of dopamine.