Novel basic catalysts are obtained by ammonia treatment of crystalline, microporous aluminosilicates (zeolites) and aluminophosphates at temperatures above 800 degrees C. The resulting materials are active catalysts in the Knoevenagel condensation of benzaldehyde with malononitrile, presumably due to the presence of nitrogen-containing species bound to the crystalline framework. While nitridation of zeolite NaY at temperatures around or below 800 degrees C does not result in an increase of the catalytic activity, ammonia treatment at 850-875 degrees C produces a significantly more active material. Further typical experimental results are presented which suggest that the activity gain seems to depend not only on the temperature of ammonia treatment but also on the structure and the chemical composition of the parent material. The novel microporous catalysts with their reasonable base strength offer the principle possibility to perform base catalyzed reactions in a shape selective manner.