The structure of TlInS ₂ layered semiconductor doped with 0.3% concentration of Mn impurity has been investigated by using x-ray diffraction (XRD) and Electron Paramagnetic Resonance (EPR) spectroscopy. The experiments were carried out to probe the local environment surrounding the Mn dopants in the crystal structure of TlInS ₂ . The interatomic distances between Mn - ions and neighboring atoms and effective valence of Mn - ions were determined. XRD - investigation indicated that the effective valence of Mn ions in TlInS ₂ is close to +4. It has been obtained that the EPR spectra of TlInS ₂ + 0.3% Mn consist of a broad resonance line stemming from interacting spins and a set of hyperfine structure lines originating from the paramagnetic ions. No EPR signal was observed in undoped TlInS ₂ semiconductors. The spectra revealed the incorporation of the paramagnetic Mn - cations with low symmetry site in the structure of host TlInS ₂ semiconductor crystal. The spin - Hamiltonian parameters of paramagnetic Mn - centers have been estimated ( and hyperfine splitting constant where z axis is perpendicular to layers). The observation of low field broad resonance lines indicates the magnetic inhomogeneity of the sample. It is assumed that weakly interacting Mn - ions in low symmetry site of host TlInS ₂ lead to the formation of spin cluster states, which can be considered as a precursor in preparation of new diluted magnetic semiconductor materials on the base of TlInS ₂ .