The fragmentation and intracluster chemical reaction processes of size-selected aniline-ammonia cluster cations [aniline(NH3)(n)](+) (n = 1-4) induced by intense femtosecond and nanosecond laser fields were investigated by tandem-type mass spectrometry. A new solute-solvent reaction to form [C5H6(NH3)(2)](+) was identified when the size of the cluster was increased to n = 4. On the basis of a quantum chemical calculation of the n = 4 cluster ion, it was inferred that one of the structural isomers of [aniline(NH3)(4)](+) is responsible for the chemical reaction through which a new type of strong intermolecular C-N bond is formed between the C5H6 moiety and one of the attached NH3 molecules. (C) 2004 Elsevier B.V. All rights reserved.