Incorporation of an adamantyl group in prototypical soluble expoxide hydrolase (sEH) inhibitors afforded improved enzyme potency. We explored replacement of the adamantyl group in unsymmetrical ureas and amides with substituted aryl rings to identify equipotent and metabolically stable sEH inhibitors. We found that aryl rings, especially those substituted in the para position with a strongly electron withdrawing substituent, afforded enzyme IC(50) values comparable to the adamantyl compounds in an ether substituted, unsymmetrical N,N'-diaryl urea or amide scaffold.