4-Aminophenol (4-Hydroxyaniline) is an organic building block. Its quantification in water samples upto the detection limit of 8×10-10mol l-1 has been proposed by employing single-wall carbon nanotubes (SWNT)-nafion film coated glassy carbon electrodes. It is present as the main contaminant in pharmaceutical formulations of paracetamol. High-performance liquid chromatographic (HPLC) method with amperometric detection has been reported for its determination in various analgesic formulations. It has been reported to be formed from the reduction of 4-nitrophenol (Nip) under metal-free conditions catalyzed by N-doped graphene (NG).