Thin films of nanocrystalline CuGaS2 chalcopyrites have been prepared by chemical vapor transport (CVT) using elements of Cu, Ga, and S with iodine as the transporting agent. Crystalline layers of CuGaS2 have been grown using various iodine concentrations but with constant source materials, growth zones temperatures and growth durations. The films were grown onto sapphire (Al2O3) substrates. The deposits obtained were nanostructures of CuGaS2 thin films and they were characterized by field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDAX), transmission electron microscopy (TEM), selected area electron diffraction (SAED), glancing angle X-ray diffraction (GAXRD), X-ray rocking curve, optical, Raman spectroscopy and by photoluminescence (PL) measurements. As-grown different iodine concentration CuGaS2 nanocrystalline thin films have shown p-type conductivity.