Some essential basics, mechanisms and properties in the chemistry of cyanine dyes are reviewed, explained and/or illustrated in the paper. This involves and/or covers the generic structure of cyanine dyes, mesomeric structures of cyanine dyes, charge of the dye unit, quaternary salts used in the preparation of cyanine dyes, mechanism of styryl cyanine dyes, mechanism of aza-styryl cyanine dyes, mechanism of acyclic merocyanine dyes, mechanism of cyclic merocyanine dyes, mechanism of aromatic squarylium cyanine dyes, mechanism of heterocyclic squarylium cyanine dyes, acid-base properties of cyanine dyes, determination of the pKa values of cyanine dyes, solvatochromism, general and specific solvent effects, mixed solvent effects, advantages of cyanine dyes and disadvantages of cyanine dyes. In addition, in the introduction section of this review article some light is shed on the uses and applications of cyanine dyes. Keywords: Cyanine dyes, basics in cyanine dyes, mechanisms of cyanine dyes, properties of cyanine dyes.