[en] Organic coolants offer a unique set of characteristics for fusion applications. Their main advantages include high temperature (670 K) but low pressure (2 MPa) operation, limited reactivity with lithium and lithium-lead, reduced corrosion and activation, good heat transfer capabilities, no MHD effects, and an operating temperature range that extends to room temperature. The major disadvantages are decomposition and flammability. The organic fluid characteristics are described in sufficient detail to allow fusion system designers to evaluate organic coolants for specific applications. Analyses are presented for organic-cooled blankets, first walls, high heat flux components and thermal power cycles. Designs are identified that take advantage of organic coolant features, yet have fluid decomposition related costs that are a small fraction of the overall cost of electricity. Particularly interesting applications include organic-cooled high heat flux components (up to about 8 MW/m²) for use with liquid metal cooled blankets. (orig.)