The present invention relates to substituted isoindole-1,3-dione compounds of Formula (I) ##STR00001## and pharmaceutically acceptable forms thereof, as .alpha..sub.1a/.alpha..sub.1d adrenoreceptor modulators for the treatment of benign prostatic hypertrophy and lower urinary tract symptoms. The present invention also relates to pharmaceutical compositions comprising said new compounds, new processes to prepare these new compounds and new uses as a medicine as well as methods of treatment.