A compound of formula Ia.C: wherein R 2 is hydrogen or C 1 -C 4 alkyl; R 3 is C 1 -C 4 haloalkyl; R 4 is phenyl, or phenyl substituted by one to three R 6; R 5 is halogen, nitro, C 1 -C 4 alkyl, C 3 -C 4 cycloalkyl, C 2 -C 4 alkenyl or C 1 -C 4 haloalkyl; A 3 and A 4 are independently C-H or N; L is a bond or methylene; B 1 --B 2 --B 3 -B 4 is -CH 2 -C=N-CH 2 -, -CH 2 -N-CH 2 -CH 2 -, -CH 2 -C=CH-O- or -CH=C-CH 2 -O-; R 1 is hydrogen, C 1 -C 8 alkyl, C 1 -C 8 alkylcarbonyl-, C 1 -C 8 alkoxy, C 1 -C 8 alkoxy-C 1 -C 8 alkyl, C 2 -C 8 alkenyl, C 2 -C 8 alkynyl, aryl or aryl substituted by one to three R 6, or R 1 is heterocyclyl or heterocyclyl substituted by one to three R 6 or C 1 -C 8 alkoxycarbonyl-; each R 6 is independently halogen, cyano, nitro, C 1 -C 8 alkyl, C 1 -C 8 haloalkyl, C 1 -C 8 alkoxy, or C 1 -Cshaloalkoxy; Y 1 is CR 7 R 8, C=O or C=S; Y 2, Y 3 and Y 4 are independently CR 7 R 8, C=O, C=S, N-R 9, O, S, SO or SO 2; wherein at least two adjacent ring atoms in the ring formed by Y 1, Y 2, Y 3 and Y 4 are heteroatoms; each R 7 and R 8 is independently hydrogen, halogen, C 1 -C 8 alkyl, or C 1 -C 8 haloalkyl; each R 9 is independently hydrogen, cyano, cyano-C 1 -C 8 alkyl, C 1 -C 8 alkyl, C 1 -C 8 haloalkyl, C 3 -Cscycloalkyl, C 3 -C 8 cycloalkyl where one carbon atom is replaced by O, S, S or SO 2, or C 3 -C 8 cycloalkyl-C 1 -C 8 alkyl, C 3 -C 8 cycloalkyl-C 1 -C 8 alkyl where one carbon atom in the cycloalkyl group is replaced by O, S, S or SO 2, or C 3 -C 8 cycloalkyl-C 1 -C 8 haloalkyl, C 1 -C 8 hydroxyalkyl, C 1 -C 8 alkoxy-C 1 -C 8 alkyl, C 2 -C 8 alkenyl, C 2 -C 8 haloalkenyl, C 2 -C 8 alkynyl, C 2 -C 8 haloalkynyl, phenyl, phenyl substituted by one to three R 10, heteroaryl, heteroaryl substituted by one to three R 10, phenyl-C 1 -C 4 alkyl, phenyl-Ci-C 4 alkyl wherein the phenyl moiety is substituted by one to three R 10, heteroaryl-C 1 -C 4 alkyl or heteroaryl-C 1 -C 4 alkyl wherein the heteroaryl moiety is substituted by one to three R 10, or C 1 -C 4 alkyl-(C 1 -C 4 alkyl-ON=)C-CH 2 -; each R 10 is independently halogen, cyano, nitro, C 1 -C 8 alkyl, C 1 -C 8 haloalkyl, C 1 -C 8 alkoxy, or C 1 -Cshaloalkoxy; or a salt or N -oxide thereof; providing that when B 1 --B 2 --B 3 -B 4 is -CH 2 -C=CH-O- or -CH=C-CH 2 -O-, Y 1 -Y 2 -Y 3 -Y 4 is not - CH 2 -O-N(R a)-C(=O)-, wherein R a is hydrogen, methyl, ethyl, propyl, isopropyl, butyl, cyclopropyl, cyclopropyl-methyl, cyclobutyl, cyclobutyl-methyl, oxetanyl, thietanyl, trifluoroethyl, difluoroethyl, allyl, propargyl, cyanomethyl, benzyl, benzyl substituted by one to three R b, or R a is pyridyl-methyl- or pyridyl-methyl- substituted by one to three R b; and each R b is independently fluoro, chloro, bromo, trifluoromethyl, trifluoromethoxy, cyano or methoxy. R 2 is hydrogen or C 1 -C 4 alkyl; R 3 is C 1 -C 4 haloalkyl; R 4 is phenyl, or phenyl substituted by one to three R 6; R 5 is halogen, nitro, C 1 -C 4 alkyl, C 3 -C 4 cycloalkyl, C 2 -C 4 alkenyl or C 1 -C 4 haloalkyl; A 3 and A 4 are independently C-H or N; L is a bond or methylene; B 1 --B 2 --B 3 -B 4 is -CH 2 -C=N-CH 2 -, -CH 2 -N-CH 2 -CH 2 -, -CH 2 -C=CH-O- or -CH=C-CH 2 -O-; R 1 is hydrogen, C 1 -C 8 alkyl, C 1 -C 8 alkylcarbonyl-, C 1 -C 8 alkoxy, C 1 -C 8 alkoxy-C 1 -C 8 alkyl, C 2 -C 8 alkenyl, C 2 -C 8 alkynyl, aryl or aryl substituted by one to three R 6, or R 1 is heterocyclyl or heterocyclyl substituted by one to three R 6 or C 1 -C 8 alkoxycarbonyl-; each R 6 is independently halogen, cyano, nitro, C 1 -C 8 alkyl, C 1 -C 8 haloalkyl, C 1 -C 8 alkoxy, or C 1 -Cshaloalkoxy; Y 1 is CR 7 R 8, C=O or C=S; Y 2, Y 3 and Y 4 are independently CR 7 R 8, C=O, C=S, N-R 9, O, S, SO or SO 2; wherein at least two adjacent ring atoms in the ring formed by Y 1, Y 2, Y 3 and Y 4 are heteroatoms; each R 7 and R 8 is independently hydrogen, halogen, C 1 -C 8 alkyl, or C 1 -C 8 haloalkyl; each R 9 is independently hydrogen, cyano, cyano-C 1 -C 8 alkyl, C 1 -C 8 alkyl, C 1 -C 8 haloalkyl, C 3 -Cscycloalkyl, C 3 -C 8 cycloalkyl where one carbon atom is replaced by O, S, S or SO 2, or C 3 -C 8 cycloalkyl-C 1 -C 8 alkyl, C 3 -C 8 cycloalkyl-C 1 -C 8 alkyl where one carbon atom in the cycloalkyl group is replaced by O, S, S or SO 2, or C 3 -C 8 cycloalkyl-C 1 -C 8 haloalkyl, C 1 -C 8 hydroxyalkyl, C 1 -C 8 alkoxy-C 1 -C 8 alkyl, C 2 -C 8 alkenyl, C 2 -C 8 haloalkenyl, C 2 -C 8 alkynyl, C 2 -C 8 haloalkynyl, phenyl, phenyl substituted by one to three R 10, heteroaryl, heteroaryl substituted by one to three R 10, phenyl-C 1 -C 4 alkyl, phenyl-Ci-C 4 alkyl wherein the phenyl moiety is substituted by one to three R 10, heteroaryl-C 1 -C 4 alkyl or heteroaryl-C 1 -C 4 alkyl wherein the heteroaryl moiety is substituted by one to three R 10, or C 1 -C 4 alkyl-(C 1 -C 4 alkyl-ON=)C-CH 2 -; each R 10 is independently halogen, cyano, nitro, C 1 -C 8 alkyl, C 1 -C 8 haloalkyl, C 1 -C 8 alkoxy, or C 1 -Cshaloalkoxy; or a salt or N -oxide thereof; providing that when B 1 --B 2 --B 3 -B 4 is -CH 2 -C=CH-O- or -CH=C-CH 2 -O-, Y 1 -Y 2 -Y 3 -Y 4 is not - CH 2 -O-N(R a)-C(=O)-, wherein R a is hydrogen, methyl, ethyl, propyl, isopropyl, butyl, cyclopropyl, cyclopropyl-methyl, cyclobutyl, cyclobutyl-methyl, oxetanyl, thietanyl, trifluoroethyl, difluoroethyl, allyl, propargyl, cyanomethyl, benzyl, benzyl substituted by one to three R b, or R a is pyridyl-methyl- or pyridyl-methyl- substituted by one to three R b; and each R b is independently fluoro, chloro, bromo, trifluoromethyl, trifluoromethoxy, cyano or methoxy.