The purpose of this study is to develop a reliable and valid neurotransmitter's measurement scale. The developed scale would be instrumental in studying the role of neurotransmitters in financial decisions making. A threefold approach was used to develop and validate the scale. The first stage was a qualitative exploratory step for item generation, second initial purification of the stage 1 findings using exploratory factor analysis, and third was validation of the scale using confirmatory factor analysis. The findings accrued an eight-dimensional second-order model of neurotransmitters (adrenaline, noradrenaline, dopamine, serotonin, GABA, acetylcholine, glutamate, and endorphins), comprising 58 items. The findings of the study provide a suggest that investors and institutions not only to re-define rationality but also to reconsider the effect of neurotransmitters on financial decisions and investment behaviour. This research contributes to the body of knowledge by defining and verifying substantial dimensions of neurotransmitters. In future studies, an eight-dimensional measurement scale could be further used as a research tool to assess how neurotransmitters are involved in our day-to-day financial decisions in different cultures.