Novel 4′-[(NR1R2-1-yl)]-propoxy-biaryl-4-carboxamides were designed and synthesized. All compounds were tested for affinity at histamine H3receptors. Most compounds were highly potent and selective for human and rat H3 receptors and selected examples such as A-349821 showed functional antagonism of H3 receptors in vitro and in a mouse dipsogenia model.