The discotic hexagonal columnar (Col(h)) liquid crystalline phases of simple benzene derivatives bearing -CONHC14H29 chains at the 1-, 3-, and 5-positions (3BC) and 1-, 2-, 4-, and 5-positions (4BC) display ferroelectricity and antiferroelectricity, respectively. The phase transition behavior, molecular assembly structures, dielectric response, and ferroelectric properties of their mixed crystals [(3BC)(1-x)(4BC)(x)] were evaluated to clarify the nanoscaling effect on the collective inversion of the one-dimensional (1D) N-H center dot center dot center dot O= hydrogen bonding interaction observed in the (3BC)(infinity) chain. A small quantity of 4BC doped into 3BC (x <= 0.03) maintained the ferroelectric polarization-electric field response (P-E) in the (3BC)(1-x)(4BC)(x) chains, where the antiferroelectric 4BC molecules in the ferroelectric 3BC column act as a pinning potential site for dipole inversion. On the contrary, a relatively large amount of 4BC doping (x >= 0.1) forms a domain separation state between the hydrogen-bonded (3BC)(infinity) and (4BC)(infinity) columns, in which the ferroelectric P-E hysteresis completely disappeared. The correlation length for the appearance of ferroelectricity in the 1D column was estimated to be similar to 40 nm in the Col(h) liquid crystalline phase of 3BC.