Photoluminescence spectra, photoluminescence decay curves and Raman scattering spectra have been investigated for stoichiometric rare-earth molybdate and tungstate compounds. NaNd(MoO 4 ) 2 and NaNd(WO 4 ) 2 show emissions due to the transition 4 F 3/2 → 4 I 9/2 in Nd 3+ . A possibility of laser oscillation in NaNd(MoO 4 ) 2 is pointed from comparisons of the emission intensity and the decay time constant with NaNd(WO 4 ) 2 where laser oscillations have been reported. In NaLa(MoO 4 ) 2 and NaLa(WO 4 ) 2 , observed emissions which are not related to La 3+ are probably due to the transitions in MoO 4 2- and WO 4 2- molecular ions, respectively, in scheelite crystal. Raman spectra of these compounds are similar, probably related to the same crystal structure. LiEr(MoO 4 ) 2 shows the emissions due to transitions 2 H 11/2 → 4 I 15/2 , 4 S 3/2 → 4 I 15/2 and 4 F 9/2 → 4 I 15/2 in Er 3+ , respectively, which are believed to be observed for the first time.