Structured layers of heat-resistant polycondensates are prepared by a process wherein ethylenically unsaturated tetracarboxylates or adducts or salts of tetracarboxylates, which still contain at least one unesterified carboxylic acid group, with ethylenically unsaturated amines, amides or onium compounds mixed with compounds which contain amino, isocyanate or blocked isocyanate groups and can be subjected to polycondensation with the tetracarboxylates are applied as a layer to a substrate, this layer is exposed through a negative, the unexposed, soluble parts are then removed and the insoluble parts are converted into the final polycondensate form at elevated temperatures.