The stability and lowest existing temperature for the rotator phase of long-chain acrylate were improved remarkably simply through the ultra-addition effect of physical blending of two long-chain acrylates, which leads to a wider operation window and better rotator-state photopolymerization. Hexadecyl acrylate (HDA) and tetradecyl acrylate (TDA) were proved existing rotator phase like previously reported octadecyl acrylate (ODA). The binary rotator phase systems were constructed by mixing HDA or TDA with ODA and investigated in detail through thermal analysis, X-ray diffraction, and photopolymerization kinetics. The chain-reaction photopolymerization conversion of the binary system significantly increased to 60% from near 0 for pure acrylate, which realized 0 + 0 = 2. The mechanism of such an ultra-addition effect was explained on the basis of X-ray diffraction data and calculation of the geometric model. The effect of difference in chain length between two components on this enhancement was studied, and a threshold value was found.