A criterion for systematization of organic compounds is described. Organic compounds (estimated to 16-20 millions) are of three types: (A) symmetric (especially meso and C2 symmetric), (B) possible symmetry generators, i.e. compounds possessing a real or imaginary, but plausible, symmetric correspondent: irrechi (from irregular distribution of chiral carbons) and constitutional), and (C) archaic (or primitive) that are neither symmetric nor possible symmetry generators. Symmetric compounds are a minority in organic chemistry. The three groups are (bio) chemically interchangeable. In preceding papers we have demonstrated that almost all natural micromolecular combinations are either symmetric or possible symmetry generators; archaic (primitive) type is also represented in natural chemistry. On the other hand, it should be stressed that symmetric compounds, both meso and C2 symmetrical (C2 symm.) have been found almost exclusively in plants and microorganisms, and they are usually produced from constitutional (constit.) precursors. A series of symmetrization/desymmetrization reactions are presented, and the proof is evidenced that they can establish a new and coherent concept in biochemistry and organic chemistry. Symmetrization reactions can be followed according to chemical type involved: oxidation, cyclization, esterification, glycosylation, methylation, etc. This approach is valid to all major classes of compounds. A dendrimeric relationship is presented within molecular formulae.

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It is believed that the place called Bermuda triangle is able to hide of human seeing objects entered its area. A Bermuda triangle in chemistry is able to hide (mask) atoms or planar molecular fragments cut by their mirror plane of symmetry, not of human eyes but, of polarized light. A triangular skeleton (frame) has been imagined, possessing the ability to cover many hundreds of molecular formulae, providing the latter refer to aliphatic, or partially aliphatic, compounds, and with a low degree of oxidation. This skeleton (frame) is based on a very general and strong principle, valid in meso entities. The idea is advanced that isomers coming up from a molecular formula could be of four types (groups): meso, C2 symmetrical (CTS), irrechi (from irregular chiral) and constitutional (constit.). The following universal rule is revealed: all CTS and irrechi can be converted to meso ones, but the reverse is not true, at least for the same skeleton. At the same time, an impressive number of constitutional natural or synthetic combinations are characterized by at least one real or envisaged meso isomer. Thus, from a structural point of view, meso isomers are justified as reference compounds. The above mentioned principles have been applied to numerous natural compounds: amino acids, lipids, carbohydrates, nucleosides, vitamins, steroids, alkaloids,  hydrocarbons. A mathematical equation sustaining the triangular representation has been proposed. One raises the question which of the four types is the upper. A tentative answer is given to this question.