Monolayer　nanosheets　of　Bi2W1-xMoxO6　solid　solutions,　possessing　an　average　thickness　of　0.98　nm,　have　been　rationally　designed　and　constructed　by　a　facile　bottom-up　route　of　a　hydrothermal　reaction.　The　tiptop　photocatalytic　efficiency　of　Bi2W1-xMoxO6　monolayer　nanosheets　can　be　achieved　for　effective　reduction　conversion　of　nitrobenzene　into　anilines　under　visible　light,　in　conspicuous　contrast　to　the　homologous　pristine　Bi2WO6　and　Bi2MoO6　components.　The　optimal　Bi2W0.25Mo0.75O6　monolayer　nanosheets　exhibit　a　high　selectivity　and　stability　for　photocatalytic　nitrobenzene　reduction,　affording　a　high　aniline　generating　rate　of　650　μmol　g-1.h-1,　in　excess　of　the　previously　reported　ordinary　photocatalysts.　The　good　photocatalytic　property　could　be　due　to　the　lattice　distortion　in　solid　solutions　for　structural　polarity　by　the　more　electronegative　W　substitution,　leading　to　the　efficient　interfacial　and　interior　separation　of　photogenerated　carriers.　The　structure-activity　relationship　of　Bi2W1-xMoxO6　demonstrates　a　novel　insight　to　devise　property-controllable　photocatalysts　at　the　atomic　level　with　high　efficiency　for　organic　photocatalytic　reactions.　©　2021　American　Chemical　Society.