<p>The industrial development and modernization occurring worldwide are crucial for meeting the demands of the present era. However, the necessary use of xenobiotics, such as heavy metals, dyes, and pesticides, poses a significant threat to ecosystems and inflicts severe harm on the environment. Cyanobacteria play a vital role in nitrogen fixation and are integral to the environment, contributing to soil fertility, UV protection, and oxygen production, among other functions. Despite the ability of these microbes to produce valuable metabolites, their production is sensitive to environmental toxicity. Furthermore, the relationship between photonic wavelength and the photosynthetic activity of cyanobacteria remains poorly understood. This article investigates the connection between the efficiency of the photosystem and the nature of the incident photonic wavelength. Additionally, the study examines the effects of photonic energy on the response of cyanobacteria to Cr (VI) toxicity, highlighting the involvement of an alternative quantum well induced by the presence of Cr (VI). Significantly, the research identifies a clear correlation between the level of photonic energy and the efficiency of the photosystem by calculating various photochemical and physiological parameters, including pigments, dry biomass, quantum yield, and transient S state. The enhancement of water-splitting processes and photosystem II efficiency was also observed with increased photonic energy under blue and green light, leading to a reduction in oxidative damage. These findings suggest a cooperative relationship between specific light wavelengths and the alleviation of Cr (VI) stress in <i>Nostoc commune</i>, providing insights into their ecological adaptability and potential applications in controlled cultivation systems and bioremediation.</p>