The conformational state and noncovalent interaction of protonated dopamine (p-dopamine) playan important role in its key and lock binding with its receptors. Hence, understanding of the role of weaknoncovalent interactions in the stability of the higher order structures of the p-dopamine is desired. In thisstudy, we have combined the spectroscopic and quantum chemical calculation studies to understand the roleof noncovalent interactions in the stability of the dimers and trimers of p-dopamine in the aqueous medium.The intensity of the UV–Visible spectra of p-dopamine increases and shows a red shift with increasing concentrations suggesting the presence of the higher order structures of p-dopamine in the aqueous medium.The quantum chemical calculations and AIM studies of the different structures of its dimer and trimerssuggest the presence of N–H₃⁺…π, C–H…π, π…π weak interactions along with conventional N–H…O hydrogen bond. The calculated peak positions of the UV–Visible spectra of different clusters show that the higher order of clusters show red shifted peak position compared to the monomer and the red shifted peak ismore evident in the clusters having noncovalent interactions.