Na2Mo2xW2(1 − x)O7 (x = 0..1 with step 0.1) compositions were obtained by solid-state synthesis and spontaneous crystallization. The sample series were studied by XRD, Raman, DSC and SEM methods. The obtained data indicates formation of solid solutions, with unit cell gradually increasing with increasing tungsten ratio. A refined Na2Mo2O7 - Na2W2O7 phase diagram with unlimited miscibility was constructed. The solidus line was built based on DSC data and the liquidus line was constructed based on spontaneous crystallization experiments data. A luminescence study showed possibility of emission color variation in Na2Mo2xW2(1 − x)O7 solid solutions in dependence from excitation wavelength.