Display omitted •Single crystal of 2l-Trp·HCl was obtained for the first time.•Crystal and molecular structure of 2l-Trp·HCl has been determined.•The existence of dimeric (l-Trp⋯l-TrpH) cation is established.•IR and Raman spectra of 2l-Trp·HCl were studied and compared with spectra of previously known l-Trp·HCl. l-Tryptophan l-tryptophanium chloride is a new salt with (A⋯A+) type dimeric cation. It crystallizes in the monoclinic system (space group P21, Z=2). The asymmetric unit contains one zwitterionic l-tryptophan molecule, one l-tryptophanium cation and one chloride anion. The dimeric cation is formed by a OH⋯O hydrogen bond with the O⋯O distance equal to 2.5556(18)Å. The infrared and Raman spectra of the crystal are studied and compared with the spectra of l-tryptophanium chloride.