This paper describes the synthesis and pharmacological evaluation of three series of compounds 4a–b, 13a–k and 19, structurally related to the known potent cysLT1 receptor antagonists RG-12553, ICI-204219 and ONO-1078, respectively. The common structural feature of these new series is the presence of a 4-quinolone nucleus acting as a template for substitution of the aromatic nucleus present in the prototype antagonists. We describe the ...