Among various CuInS2-rerlated heterojunctions, it is expected that CIS-based p−n junctions are high-performance photo-active electrodes. Herein, both n-type and p-type CuInS2 thin films were synthesized via facile successive ion layer adsorption and reaction (SILAR) method, using aqueous (A-CIS) and mathanolic (M-CIS) SILAR solutions, respectively. Based on UV-visible transmission spectra, M-CIS thin films were more transparent with larger band gap energy (1.6 eV) than A-CIS thin films (1.5 eV). The A1-mode Raman peak of M-CIS thin film was located at 293 cm-1 which has a red shift of 5 cm-1 as compared to A-CIS one, indicating that M-CIS has smaller CuInS2 nanoparticles. The Mott-Schottky plots revealed that A-CIS is an n-type semiconductor, while M-CIS thin films have p-type semiconducting behavior, which is due to different Cu/In ratio in these thin films. The obtained results can be very useful to prepared CIS-based p-n junctions toward high performance solar-based devices.