We have synthesised a Co centred and an In centred MOF which represent the first examples of MOFs in which the channels are functionalized by both acidic carboxyl and basic pyridyl groups. These compounds present an opportunity to shed light on the interactions between the adsorbed molecules and the framework. In particular the perturbations of the rotational levels of hydrogen give information on the nature of the adsorption site. TOSCA has an excellent resolution of the hydrogen rotational line and by studying the changes in the position of the rotational line as function of loading it is possible to obtain very precise site by site adsorption isotherms.