Nitration of commercial full aromatic β-carboline alkaloids nor-harmane (1), harmane (2), harmine (3), harmol (4), and the 7-acetylated derivative of harmol (5) is described. Advantages and disadvantages of different nitration reagents which involve acidic conditions (HNO 3 /H + ) and neutral conditions (Cu(NO 3 ) 2 ; ceric ammonium nitrate) are discussed. A complete 1 H and 13 C-nmr characterization including ms and also uv absorption spectra in neutral and acid media is presented. A detailed ei-ms and ld-tof-ms study is enclosed because the nitro-β-carbolines constitute a new family of β-carboline-like chromophores with potential use as matrix in uv-maldi-tof-ms.