Ab initio and density functional theory methods have been applied to study the molecular structure and interaction of water with N-methyl-2-propenylidenimine and N-methyl-2-butenylidenimine molecules. The most possible reactive sites of the above molecules have been identified for the water interactions. The strength of the hydrogen bond is discussed using the atomic charges, which were calculated using the Mulliken population analysis and Natural population analysis schemes at MP2/6-31G* level of theory. The electron density (rho) and laplacian of electron density (del(2)rho) have been calculated for the possible existence of the hydrogen bonds with CH and CH3 groups of molecules using the "Atoms in molecules" approach. The chemical hardness and chemical potential for these complexes have been calculated at HF/6-31G* level of theory and discussed for the conformational stability of these molecules.