With the aim to develop new ligands able to discriminate among the three subtypes of α1- adrenergic receptors (α1A-AR, α1B-AR, and α1D-AR), a series of new 1, 2, 3, 9-tetrahydro- 4H-carbazol-4-ones bearing a 3-[[[2-(4-hydroxyphenyl) ethyl] amino] methyl] or a 3-[[4-(2- substitutedphenyl) piperazin-1-yl] methyl] side chain were synthesized. The general structure of the new compounds is reminiscent of HEAT and RN5, two potent α1-AR ...