This Special Issue of Chemical Monthly is dedicated to lectures and posters presented at the XXIVth European Colloquium on Heterocyclic Chemistry (ECHC), which was held on August 23–27, 2010, at the Vienna University of Technology. This series of meetings was initiated in 1974 in the French-speaking areas of Western Europe. Since then the ECHC, which is currently taking place biennially, has developed into a true European event, as some recent venues demonstrate: Antwerp (Belgium, 2008), Bari (Italy, 2006), Sopron (Hungary, 2004), Stockholm (Sweden, 2002), and Aveiro (Portugal, 2000) have hosted the first colloquia of this millennium.

The XXIVth ECHC covered all aspects of heterocyclic chemistry, with special focus on novel methods in heterocyclic synthesis and the application of heterocycles in medicinal chemistry, agrochemistry, sustainable chemistry, and materials. Twelve plenary lectures, twelve invited lectures, twelve oral short communications, and more than 150 posters were presented to over 300 participants from countries all over the world.

This issue comprises reviews and original papers from all types of lectures as well as poster presentations. The diversity of topics covered mirrors the importance and spreading of heterocyclic compounds in chemistry and related scientific areas. For example, the issue includes contributions on macroheterocyclic dyes, model systems for the green fluorescent protein chromophore, enantioselective synthesis of prolines, allenes as building blocks in heterocyclic synthesis, and organophosphorus compounds. Enjoy reading!