Five heteroanionic oxybromides, , , , , and , were grown by a high-temperature salt flux method. Millimeter-sized crystals were collected after salt flux was removed by DI water. The crystal structures were accurately determined by single-crystal X-ray diffraction. is isostructural to . The substitution of lanthanum for rare earth elements does not change the crystal structure. is the first acentric tungsten-containing compound of the (RE = Y, La–Lu; VI = Mo, W) system. The bonding picture of was understood by crystal orbital Hamilton population calculations (COHP) and electron localization function (ELF) analysis, which confirmed the uncommon 4 + 1 coordination of tungsten surrounded by oxygen atoms. Linear optical properties such as bandgaps, infrared spectrum (IR), and birefringence of the title compounds were recorded in this work. exhibits a moderate second harmonic generation (SHG) response of 0.47× (KDP) for incident 1064 nm radiation. and exhibit superior SHG responses of 1.66× KDP and 3.71× KDP for samples for incident 1064 nm radiation, respectively. All measured samples exhibited type-I phase matching behavior. Density function calculations (DFT) verified that the optical properties of and are predominantly controlled by units. Via the rare earth elements Sm and Dy doping, and emit visible lights of various wavelengths upon UV light excitation. The distortion of lambda-shaped one-dimensional (1D) strands plays an important role in enhancing nonlinear optical properties and photoluminescent properties within and compared with .