wherein R.sub.3 is Alk.sub.14ArR.sub.16, and wherein Alk.sub.14 is C.sub.1-8 straight or branched alkylene or alkenylene. The present invention provides novel adenosine receptor antagonists, more particularly, A.sub.1 adenosine receptor antagonists of formula (I). Pharmaceutical compositions comprising an A.sub.1 adenosine receptor antagonist of formula (I) and a pharmaceutically acceptable carrier are further provided. Compositions also include diagnostic assay-type probes comprising a novel A.sub.1 adenosine receptor antagonist of formula (I) that is labeled or conjugated with radioactive or non-radioactive material. Methods for treating A.sub.1 adenosine receptor related disorders comprising administering an A.sub.1 adenosine receptor antagonist of formula (I) are also disclosed. The novel A.sub.1 adenosine receptor antagonist compositions of formula (I) find further use in diagnostic and imaging methods.