The present invention relates to substituted 1,2,5-oxadiazole compounds of the formula I and the N-oxides and salts thereof and to compositions comprising the same. The invention also relates to the use of the 1,2,5-oxadiazole compounds or of the compositions comprising such compounds for controlling unwanted vegetation. Furthermore, the invention relates to methods of applying such compounds. In formula I, the variables have the following meanings R is e.g. hydrogen, cyano, nitro, halogen, C1-C6-alkyl, C3-C7-cycloalkyl, C3-C7-cycloalkyl-C1-C4-alkyl, C1-C6-haloalkyl, C2-C6-alkenyl, C2-C6-haloalkenyl, C2-C6-alkynyl, C2-C6haloalkynyl, C1-C4-alkoxy-C1-C4-alkyl, C1-C4-haloalkoxy-C1-C4-alkyl, O&mdash；Ra, Z&mdash；S(O)n&mdash；Rb, Z&mdash；C(&boxH；O)&mdash；Rc, Z&mdash；C(&boxH；O)&mdash；ORd, Z&mdash；C(&boxH；O)NReRf, Z&mdash；NRgRh, Z-phenyl and Z-heterocyclyl etc； R1 is e.g. Z1-cyano, halogen, nitro, C1-C8-alkyl, C2-C8-alkenyl, C2-C8-alkynyl, C1-C8-haloalkyl, C1-C8-alkoxy, C1-C4-alkoxy-C1-C4-alkyl, Z1&mdash；C1-C4-alkoxy-C1-C4-alkoxy, C1-C4-alkylthio-C1-C4-alkyl, Z1&mdash；C1-C4-alkylthio-C1-C4-alkylthio, C2-C6-alkenyloxy, C2-C6-alkynyloxy, C1-C6-haloalkoxy, C1-C4-haloalkoxy-C1-C4-alkyl, Z1&mdash；C1-C4-haloalkoxy-C1-C4-alkoxy, Z1&mdash；S(O)k&mdash；R1b, Z1-phenoxy and Z1-heterocyclyloxy； R2, R3 are identical or different and e.g. hydrogen, halogen, Z2&mdash；OH, Z2&mdash；NO2, Z2-cyano, C1-C6-alkyl, C2-C8-alkenyl, C2-C8-alkynyl, Z2&mdash；C3-C10-cycloalkyl, Z2&mdash；C3-C10-cycloalkoxy, C1-C8-halo alkyl, Z2&mdash；C1-C8-alkoxy, Z2&mdash；C1-C8-haloalkoxy, Z2&mdash；C1-C4-alkoxy-C1-C4-alkoxy, Z2&mdash；C1-C4-alkylthio-C1-C4-alkylthio, Z2&mdash；C2-C8-alkenyloxy, Z2&mdash；C2-C8-alkynyloxy, Z2&mdash；C1-C8-haloalkoxy, Z2&mdash；C2-C8-haloalkenyloxy, Z2&mdash；C2-C8-haloalkynyloxy, Z2&mdash；C1&mdash；C4-haloalkoxy-C1&mdash；C4-alkoxy, Z2-(tri-C1-C4-alkyl)silyl, Z2&mdash；S(O)k&mdash；R2b, Z2&mdash；C(&boxH；O)&mdash；R2C, Z2&mdash；C(&boxH；O)&mdash；OR2d, Z2&mdash；C(&boxH；O)&mdash；NR2gR2f, Z2&mdash；NR2gR2
