A series of N-[(1H-heteroaryl)alkyl]-1H-isoindole-1,3(2H)-diones were prepared as part of a continuing investigation into the biological properties of compounds that were both thromboxane synthetase inhibitors and potential antihypertensive agents. The most active thromboxane synthetase inhibition was found for the title imidazole derivatives wherein a hexyl or octyl chain separated the heterocyclic ends of the molecule (5,6) or with substitution on the isoindole portion of the molecule (18, 19, 21, 22, 25, 26). Compounds with shorter alkyl chain separations had good antihypertensive effects (1-5, 8-10, 19-22, 27-30). Butyl derivative 3 was chosen for further evaluation as a potential antihypertensive agent with thromboxane synthetase inhibitory properties.