Carbon based materials are highly promising materials for environmental applications. In the current study, sulphur doped graphite like carbon nitride (S-g-C3N4) samples were prepared through thermal polymerization of thiourea at different conditions. The carbon content in the prepared samples was controlled by varying the calcination temperature and calcination time and its effect on the properties of the samples was investigated. The XRD studies confirmed the formation of g-C3N4 while the SEM investigations were performed to monitor the morphology transformation as a function of the preparation conditions. Changing the preparation temperature was found to strongly impact the carbon content in the g-C3N4 nanostructures and consequently their morphological and optical properties including their band gap and photoluminescence characteristics. Additionally, varying the calcination time was found to play a role in modifying the properties of the samples but with slightly less effect than that of the calcination temperature. These parameters were utilized to enhance the photocatalytic performance for water treatment applications. The findings of the study show that engineering the composition of S doped g-C3N4 samples by combining the effects of various preparation conditions could be effectively utilized to enhance the properties of g-C3N4 and its performance in many vital applications.