A series of novel isochromanone based urotensin II receptor agonists have been synthesized and evaluated for their activity using a functional cell based assay (R-SAT). Several potent and efficacious derivatives were identified with 3-(3, 4-dichlorophenyl)-6, 7- dimethyl-3-(2-dimethylaminoethyl) isochroman-1-one (28) being the most potent compound showing an EC50-value of 51nM, thereby being the most potent compound so far within ...