The using of mixed methodology in banking and finance research has long been in debate. Social science researchers focus on the philosophy and epistemology to validate their findings. In the absence of the laboratories and practical tests, the social science researchers use the mixed methodologies to legitimate their work and validate the findings. It is worth mentioning that, the selection of an appropriate methodology is vital to ensure the validity and reliability of findings in any research, especially finance and banking. Therefore, the purpose of this paper is to explain that how the researchers can mix two different types of methodologies (Qualitative and Quantitative) in the banking and finance research to validate their findings. The paper has been designed in a way to explain the advantages and disadvantages of both the research methodologies and then demonstrated how mixed methodology can be used in one single study, by using the case study of nanotechnology firms in getting finance from banks as a subject. Both quantitative and qualitative research methods have disadvantages or weaknesses, but the triangulation or the use of mixed methodology together with multiple data sources can make research findings more valid and reliable. The findings from mixed method are combined in the study in order to deeply understand the nature of research. Furthermore, the weaknesses of one method can be reduced by the strength of the other method.