The existence of intramolecular dihydrogen bonding in the main group elements is investigated at the ab initio level of theory. The AH(n)-XHm complexes (with A = Li/B/Al and X= F/O/N/Cl/S/P) in general do not show intramolecular dihydrogen bond (DHB) in their equilibrium structures; however, it is observed in the transition state for the dehydrogenation reaction AH(n)-XHm --> AH(n-1)-XHm-1 + H-2. The barriers to these reactions have been calculated and are found to be least for the complexes having DHB in the equilibrium structure or having eclipsed geometry favorable for DHB formation. The topological analysis of electron density distribution provides crucial information on the existence of DHB as well as on the extent of the dehydrogenation reaction. The above features indicate that the motivation for the formation of intramolecular DHB is likely to facilitate the dehydrogenation reaction from complexes similar to AH(n)-XHm.