The field of biosensing has made significant strides in detecting neurotransmitters and signaling molecules critical to physiological functions. This chapter delves into advanced methodologies for sensing dopamine and nitric oxide (NO), pivotal in neuroscience and biomedical research. Dopamine, a neurotransmitter crucial for motor control and reward mechanisms, is effectively detected using electrochemical sensors. Innovations such as graphene and metal nanoparticles enhance sensor sensitivity and selectivity. Ionic liquid composite electrodes enable robust in vitro and in vivo dopamine detection, promising advancements in clinical diagnostics and neuroscience research. Nitric oxide, a fleeting signaling molecule with diverse physiological roles, presents challenges in detection due to its low concentrations and rapid turnover in tissues. Electrochemical methods employing platinum, gold, and graphene-based electrodes offer sensitive NO detection. Techniques involving electrode modification with selective membranes, biomolecules, and nanomaterials improve specificity and enable precise measurement of NO levels in cells and tissues. These advancements are pivotal in understanding cardiovascular health, immune response modulation, and neuronal signaling pathways. Graphene, with its exceptional electrical, mechanical, and biocompatible properties, emerges as a key material in biosensing. Its integration into electrode designs enhances sensor performance, providing high sensitivity, rapid response times, and improved bio-interfacing capabilities. The chapter highlights graphene's role in advancing electrode conductivity, stability, and biocompatibility, thereby pushing the boundaries of biosensor technology. This chapter underscores the interdisciplinary efforts in electrochemistry, materials science, and biomedical engineering aimed at developing advanced biosensors for dopamine and NO. These innovations not only deepen our understanding of neurotransmitter dynamics and physiological signaling but also hold promise for transformative applications in disease diagnostics, personalized medicine, and neuroengineering.