Bifunctional aromatic derivatives that act as both beta(2) agonists and muscarinic receptor antagonists are claimed. The compounds use two separate pharmacophoric groups, coupled by a long lipohilic chain, to provide the desired biological activities and with the aim of providing a long duration of action. The compounds are claimed to be useful in the treatment of both asthma and chronic obstructive pulmonary disease and represent the first disclosure of a new concept - muscarinic antagonist-beta(2) agonists.