The present invention relates to novel isothiazolopyridones (isothiazolopyridone derivatives), to processes for preparing these compounds, to compositions comprising these isothiazolopyridones, and to the use thereof as biologically active compounds for controlling harmful microorganisms in crop protection and in the protection of materials, especially for controlling fungi, preferably for controlling fungi in plants or plant seeds.本發明係關於新穎之異噻唑并吡啶酮(異噻唑并吡啶酮衍生物),這些化合物之製備方法,含這些異噻唑并吡啶酮之組成物,及其作為生物活性化合物在農作物保護及在材料保護中用於控制有害的微生物之用途,尤其是用於控制真菌,優選是在植物或植物種子中用於控制真菌。