Recently, the synthesis of organic materials with high porosity has received considerable scientific interest, and various chemical approaches have been applied to the build-up of microporous polymer networks. In a novel catalyst-free process using Schiff base chemistry, melamine has been reacted with various di- and trivalent aldehydes to form a series of highly cross-linked microporous aminal networks with BET surface areas as high as 1377 m(2)/g and a NLDFT micropore volume of up to 0.41 cm(3)/g. It was shown that through the proper choice of the starting compounds the porosity of the final material can be fine-tuned. The materials contain up to 40 wt % of nitrogen and were also found to exhibit high thermal stability. Owing to the cheap and abundant monomers used in this study these networks are promising candidates for large-scale applications in gas storage, gas separation, catalysis, and sensing.