In this study, twelve compounds having 2-methyl-4-aryl-4,6,7,8-tetrahydro-5(1H)-quinolone structure have been synthesized by the reaction of 4-aryl-3-butene-2-on derivatives with 1,3-cyclo-hexanedione analogs in the presence of ammonium acetate In methanol. The structures of the compounds have been elucidated by 1R, H-1-NMR, C-13-NMR, mass spectroscopy and elementel analysis. Their potassium channel opener activities have been investigated on isolated rabbit bladder smooth muscle using pinacidil (CAS 85371-64-8) as standard. The test compounds and pinacidil caused concentration-dependent relaxation responses in bladder smooth muscle strips precontracted with 80 mmol/L KCI with the efficacy order: pinacidil >= 3g 3j >= 3a >= 3l = 3i >= 3c=3b >= 3d >= 3h >= 3k. In bladder smooth muscle strips precontracted with 15 mmol/L KCI, the efficacy order was: pinacidil > 3h >= 3c >= 3j >= 3g >= 3l >= 3i=3b >= 3k >= 3f >= 3a. The test compounds and pinacidil caused concentration-dependent Inhibition of electrical field stimulation-evoked contractile responses in the bladder smooth muscle strips with the efficacy order: 3j >= 3l >= pinacidil >= 3k >= 3h >= 3a >= 3g >= 3c >= 3i >= 3b >= 3f.