N-Disubstituted aniline derivatives of the formula I where R is C1-C4-alkyl, C1-C4-alkoxy, C2-C4-alkoxyalkyl or halogen, R1 is C1-C4-alkyl or halogen, R2 is hydrogen, C1-C4-alkyl or halogen, R3 is CH[OR5]2, COOR5 or COSR5, R5 being C1-C4-alkyl, and R4 is unsubstituted or methyl-, nitro- or halogen-substituted 1,2,3-thiadiazol-4-yl or 1,2,3-thiadiazol-5-yl, and the manufacture thereof. The novel compounds have microbicidal properties.