Single-phased white light emitters made of semiconductor bulk materials are most desirable for use in white light-emitting diodes (WLEDs) based on both photoluminescence and electroluminescence. Here we demonstrate Cd and/or Se substituted double-layer [Zn2S2(ha)] (ha = n-hexylamine) hybrid semiconductors emit bright white light in the bulk form and their emission properties are systematically tunable. The ternary Zn2–2xCd2xS2(ha) hybrid compounds exhibit two photoluminescence (PL) emission peaks, one of which being attributed to band gap emission, and the other resulting from Cd doping and surface sites. The Cd concentration modulates the optical absorption edge (band gap) and the positions of the two emission bands along with their relative intensities. The ZnS-based hybrid structures (with a nominal Cd mole fraction x = 0.25) emit bright white light with significantly enhanced photoluminescence quantum yield (PLQY) compared to its CdS-based hybrid analogues. For the quaternary Zn2–2xCd2xS2–2ySe2y(ha) c...