<p>Functional near-infrared spectroscopy (fNIRS) is a non-invasive neuroimaging technique for assessing cerebral function, combining excellent ecological validity with high temporal resolution. However, despite the advantages of fNIRS, challenges remain including insufficient spatial resolution, and bulkiness—issues that conventional fNIRS devices inadequately address, particularly given the notable increase in equipment bulk and costs associated with enhancing resolution by increasing the number of detectors. In this study, we propose a scientific complementary metal-oxide-semiconductor (sCMOS) sensor as a viable alternative to fNIRS detectors. The sCMOS sensor offers a two-dimensional array sensor that replaces the traditional configuration of multiple diode-lock-in amplifiers, significantly reducing both the size and cost of the devices. However, this raises a crucial question: can the sCMOS sensor effectively substitute traditional detectors while maintaining comparable accuracy to the weak scattered light characteristic of fNIRS? To address this question, we conducted comprehensive validation through both in vitro optical performance (including scattering-absorption and blood-doped tissue-simulating phantoms) and in vivo cortical response. Our results demonstrate that the developed sCMOS-based fNIRS system achieves detection performance comparable to conventional fNIRS technologies, indicating strong potential for translational applications.</p>