The advancements in mathematical and statistical applications in chemistry (and related fields of science and industry) and the rapid developments of optical and microelectronic technologies used in chemical instruments with computers for controlling devices, managing system operation, data acquisition, and reporting experimental results gave rise to the emergence of a new scientific discipline known as chemometrics for the qualitative and quantitative resolution of complex systems containing chemicals or pharmaceuticals. Over the years, chemometrics has become a promising interdisciplinary intersection with a significant impact on analytical chemistry and its neighboring branches. In the applications of the basic theory and methodology in research and development projects, a chemometric process covers two different options including development of new theories and algorithms for processing chemical data, and new applications of the chemometric techniques to different fields of chemistry, for example, analytical chemistry, medicinal chemistry, environmental chemistry, food chemistry, agricultural chemistry, and chemical engineering. In general, chemometrics is used in the mentioned areas to solve the problem of qualitative and quantitative analysis and others. Obviously, chemometrics provides researchers efficient ways to solve complex chemical problems for the desired goal. The major aim of chemometrics is to extract more useful information from signals such as spectra, voltammogram, chromatogram, and other several formats obtained from chemical instruments.