Derivatives of 2,2’:6’,2 ":2 ",6"’-quaterpyridine have been prepared which are asymmetrically substituted with alkyl groups in the 4- or 6-position and with various substituents in the 4’-position. These ligands form dicopper(I) double helicates which have been investigated by H-1 and C-13 NMR spectroscopic techniques. The formation of helical isomers is shown to depend on the intramolecular interactions between the constituent helicands of the double helicate; 4’-methyl substituents undergo steric interactions with the 4-substituent of the partner helicand, leading to a modest selectivity, although bulky 4-substituents decrease selectivity. In the absence of 4’-substituents, the smaller pitch permits steric interactions between like 4-substituents of the component helicands. In each case, formation of the head-to-head helicate isomer is preferred.