Heteroaromatic compounds of the formulae IA and IB ##STR1## where the dashed line is a double bond between the carbon atom and a Z atom, and the index and the substituents have the following meanings:R.sup.1alkyl, alkoxy, alkylaminoR.sup.2alkyl;Aa direct bond; alkylene, alkenylene, alkynylene; O, S, S-oxides, N and alkylene derivatives or oxime radicals thereofBhydrogen, halogen,alkyl, alkenyl, alkynyl; cycloalkyl, cycloalkenyl, cycloalkynyl, heterocyclyl, aryl, hetarylUCH.sub.2, CHCl, CHR.sup.2 or NOR.sup.2 ;Xhydrogen, cyano, nitro, halogen,alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, heterocyclyl, aryl, hetaryl; oxi- and thio derivatives thereof, carbonyl derivatives thereof, carbonyloxy derivatives thereof, amino derivatives thereof, oxime derivatives thereof,amino which may bear one or two of the abovementioned groups;m1 or 2,Yoxygen or sulfur;Z.sup.1 -Z.sup.2, Z.sub.3 -Z.sub.4,together with the carbon atom to which they are bonded, are the radical of a heteroaromatic, and fungicides containing these compounds.