Presents a survey of the history and development of the blue, green, violet, orange, and brown synthetic organic artists' pigments discovered, produced, and used in the 20th century. The following organics are described: copper phthalocyanine blue, metal-free phthalocyanine blue, indanthone blue, phthalocyanine green, pigment green B, nickel-azo-yellow, quinacridone violet, dioxazine purple, dinitraniline orange, perinone orange, and PV Fast Brown HFR. The chemical identification can be done by microchemical color reactions, microcrystallizations, laser microspectral analysis, and infrared spectrophotometry. These methods of analysis together with the discovery dates of the individual pigments enable dating modern works of art (a date <i>post quem</i>) and detection of forgeries.