Synthesis and characterization of DA(8/1)OMe (14-(4＇-[(methoxy)methoxy] biphenyl)-10,12-tetradecadiynoic acid) and DA(8/1)NBP (14-(4＇-[(nitro)methoxy] biphenyl)-10,12-tetradecadiynoic acid) are presented. Monolayers of DA(8/1)OMe at gas-water interface were investigated. It does not forma stable monolayer nor does it undergo polymerization at the gas-water interface. However, the Ba2+ and Cd2+ salts formed stable monolayer that polymerized. Polymerization was confirmed by Raman spectroscopy. The diacetylene analog with the more polar tail group, DA(8/1)NBP, does not form a monolayer and undergo polymerization regardless of the subphase condition. A mixed monolayer of DA(8/1)OMe and DA(8/1)NBP forms a true monolayer if the composition of DA(8/1)NBP is 50% or less.