The Fourier transform infrared spectra of the II-bonded complexes between HCl and 4-aminopyridine, 4-aminopyrimidine, 4-hydroxypyridine, 2-hydroxypyridine, benzimidazole and purine were investigated in Ar matrices. From the analysis of these spectra, the II-bonds N ... HCl appear to be of the pseudosymmetric type II for 4-aminopyridine, 4-aminopyrimidine and 4-hydroxypyridine, while benzimidazole forms a slightly weaker complex. II-bonding of HCl with the bases 2-hydroxypyridine and purine is of the intermediate type I --> II. In the case of 4-aminopyrimidine, additional bonding of the Cl atom of HCl to an amino N-H bond yields a closed complex which explains the type II behaviour. In all other cases, bonding of additional HCl molecules to the 1:1 complexes results in proton transfer towards N-H+... Cl-...(HCl)(n) species, but n is much lower for type II than for the intermediate type I --> II complexes. The results allow us to investigate the vibration correlation diagram and the isotopic ratio nu(HCl)/nu(DCl) for B . HCl complexes in Ar matrices into more detail.