Compound of formula (I) ** Formula ** in which R1 represents a heteroaryl group of formula ** Formula ** in which * means the junction points with the dihydropyrazzolone ring, A means in any individual occurrence C-R4 or N, representing a maximum of two ring members A at the same time N, where R4 in each individual case, independently of one another, represents hydrogen or a substituent selected from the group of fluorine, chlorine, bromine, cyano, nitro, alkyl ( C1-C6), hydroxy, (C1-C6) alkoxy, trifluoromethoxy, amino, mono (C1-C6) alkyl, amino, di (C1-C6) alkyl, amino, hydroxycarbonyl and (C1-C6) alkoxycarbonyl , the said (C1-C6) alkyl moiety may be substituted for up to three times, the same or different, with fluorine, chlorine, bromine, cyano, hydroxy, trifluoromethoxy, (C1-C4) alkoxy, amino, monoalkyl (C1- C4) -amino, di-(C1-C4) alkyl-amino, hydroxycarbonyl and / or (C1-C4) alkoxycarbonyl, and E means O, S or N-R5, where R5 represents hydrogen or (C1-C6) alkyl, R2 represents a heteroaryl group of formula ** Formula ** in which it means the junction points with the dihydropyrazzolone ring, G means respectively C-R6 or N, not representing N more than one of the two G-ring members, wherein R6 in each individual case, independently of one another, represents hydrogen or a substituent selected from the group of fluorine, chlorine, bromine, cyano, (C1-C6) alkyl, cycloalkyl (C3-C6) , 4 to 6 membered heterocycloalkyl, phenyl, 5 or 6 membered heteroaryl, -C (>; = O) -OR10, -C (>; = O) - NR11R12, -OC (>; = O) -R13, -OC ( >; = O) -NR14R15, -NR16-C (>; = O) -R17, -NR18-C (>; = O) -OR19, -NR20-C (>; = O) - NR21R22, -NR23-SO2-R24, -OR28 and -NR30R31, where (i) (C1-C6) alkyl may be substituted for its part one to three times, the same or different, with moieties selected from the group of fluorine, chlorine, bromine, cyano, cycloalkyl (C3 -C6), 4-6 membered heterocycloalkyl, phenyl, 5- or 6-membered heteroaryl, -C (>; = O) -OR10, -C (>; = O) -NR11R 12, -OC