CuAlS_2 single crystals were grown by the chemical vapour transport (CVT) technique using iodine as a transporting agent in a close-spaced geometry. The crystal structure, lattice constants, Miller indices, density and %d errors of as grown CuAlS_2 were determined from X-ray diffraction (XRD). The crystalline nature was confirmed by the selected area electron diffraction (SAED) pattern of transmission electron microscopy (TEM). The Scanning Electron Microscopy (SEM) images of the as grown surfaces of the single crystals showed the layer growth mechanism. The variation of resistivity with temperature was studied along the perpendicular to the c-axis using the four probes technique. The activation energy values were evaluated from the slopes of the resistivity variation with temperature plot. The Hall measurement data at ambient temperature were used to determine the resistivity (ρ), Hall coefficient (R_H), carrier concentration (η), Hall mobility (μ), and conductivity type of the grown crystals. The hot probe method was used to confirm the conductivity type. Values of the Fermi energy (E_f ), constant values (A), scattering parameter (s), Seebeck coefficient (S), effective density of states (N_A) and effective mass (m_e∗) were determined by the data of the Seebeck coefficient variation with temperature. The I-V characteristics study was carried out in dark as well as under white and UV illumination. The high pressure electrical resistance measurements have been performed on as grown single crystals up to a pressure of 5 GPa. It was observed that the resistance decreases with pressure up to some point, then afterward increases gradually with pressure. Thermogravimetric (TG), differential thermal analysis (DTA), and differential thermogravimetric (DTG) analysis were carried out on the as grown CuAlS_2 single crystals in an inert nitrogen atmosphere in the temperature range from room temperature to 1223 K. The kinetic parameters were determined employing nonmechanistic equations using the Broido and Coats-Redfern (C-R) relations. All the obtained results are discussed in this paper.