The concept of employing a central air hole in the core is exploited to obtain an ultralarge negative dispersion photonic crystal fiber (PCF) over the wavelength range of 1350 to 1650 nm. The results show that the fiber may exhibit an average dispersion well over −500 ps/nm-km with a flattened dispersion profile. It is also found that the fiber shows a high birefringence in the order of 10−2 over the entire wavelength bands of interest. The endlessly single-mode behavior of PCFs is utilized to ensure the single modedness of the proposed fiber. Also, the technique of liquid crystal infiltration is exploited to suppress one of the two orthogonal modes of the fundamental mode. Along with the single-polarization behavior, the fiber shows an even more negative dispersion profile with less dispersion variation.