Applications of combined diatomics-in-molecules / ab initio approaches to Ne_n⁺, Ar_n*, Ar_nCl₂, and Ar_nNO clusters are discussed. Simple perturbative models within these procedures are suggested to interpret the predicted cluster structures, obtained using a basin-hopping global optimisation algorithm. The topological peculiarities of the Ar-NO potential are analysed in terms of the perturbation of the Ar-N and Ar-O interactions within the complex. The correlation between the solvation of a chromophore species in the cluster and the relative strength of the solvent-solvent and chromophore-solvent interactions is also analysed.