This review describes the synthetic approaches to tetrathiafulvalenes (TTF) and their selenium analogs-tetraselenafulvalenes (TSeF). Synthetic methods are conveniently classified according to the general mechanistic paths found in the literature. Preparation of the precursors of tetrathia- and tetraselenafulvalenes, namely 1,3-dithiole and 1,3-diselenole derivatives, are also surveyed. The scope and limitations of each method for tetrathia- and tetraselenafulvalene synthesis are discussed in relation to synthetic methods for tetrathioethenes and reactivities of these precursors. Finally, chemical properties of tetrathiafulvalenes and some physical properties of charge transfer salts of tetrathia- and tetraselenafulvalenes are briefly described. 1. Classification of Synthetic Methods to Tetrathiafulvalenes (TTF) and Tetraselenafulvalenes (TSeF) 1.1. Deprotonation of 1,3-Dithiolium Ions 1.2. Desulfurization of 2-Thioxo-1,3-dithioles and Analogous Reactions 1.3. Reaction of Acetylenes with Carbon Disulfide 1.4. Pyrolysis of Orthothiooxalates 1.5. Decomposition of the Sodium Salts of Tosylhydrazones of Dithiocarbonates 1.6. Decomposition of 2-Alkoxy-1,3-dithioles 2. Preparation of 2-Thioxo-1,3-dithioles, 2-Oxo-1,3-dithioles, and their Selenium Analogs 2.1. Reaction of Sodium Acetylenide with Carbon Disulfide and Sulfur, and Anomalous Reactions with Selenium Compounds 2.2. Reaction of Ethylene Di- or Trithioacarbonates with Acetylenes 2.3. Cyclization of ß-Keto-O-Alkyl Dithiocarbonates 2.4. Dehydrobromination of 4-Bromo-2-oxo-4,5-dihydro-1,3-dithioles 2.5. Reaction of Disodium Salt of Dimercaptomaleonitrile with Thiophosgene or Phosgene 2.6. Reaction of 2-Immonium-1,3-diselenolium Salts with Hydrogen Sulfide 2.7. Miscellaneous Methods 3. Scope and Limitations of Current Tetrathia- and Tetraselenafulvalene Syntheses 4. Reactions and Properties of Tetrathia- and Tetraselenafulvalenes 4.1. Reactions of Tetrathiafulvalene Derivatives 4.2. Charge Transfer Salts of Tetrathia- and Tetraselenafulvalenes with Electron Acceptors