A tweezers-type dicarboxylic acid (1), which has two chiral (R)-1,1'-binaphthyl systems bridged by a 2,5-(p-tolyl)thiophene spacer, exhibited the Cotton effect at 337 nm (Delta epsilon-16.5) in its CD spectrum in chloroform. This is attributable to the twisted spacer and the mechanism for the appearance of this effect is discussed. (C) 1999 Elsevier Science Ltd. All rights reserved.