This chapter reviews quantum-well structures with binary ZnSe wells. The barrier materials are ZnS, Zn(S,Se), (Zn,Mg)Se, (Zn,Mg)(S,Se), (Zn,Mg,Be)Se, (Zn,Mn)Se, and MgS. The crystallographic structure of all QW structures described here is zincblende although some bulk materials might crystallize in other phases. Properties of QWs with (Zn,Mn)Se barriers are only discussed in case they are not affected by the specific magnetic properties of the barriers. The properties of superlattices are included in this chapter if they are not determined by the interwell coupling or by the superperiodicity. Thermal activation of quantum-well excitons into the barriers is one of the reasons for the quenching of the photoluminescence and thus crucial for optical-device performance. Various excitonic resonances related to higher-order index subbands as well as 2s exciton transitions are observed in one- and two-photon absorption photoluminescence excitation spectrum experiments on ZnSe/Zn(S,Se). Photo-reflectance spectra of ZnSe/(Zn(S,Se) SQWs are shown. Strain and piezoelectric effects in (h11)-oriented ZnSe/ZnS QWs are investigated in literature. A transient Franz-Keldysh effect is reported for ZnSe/Zn(Se,S) structures. The saturation of lh and hh excitons in tensile strained ZnSe/(Zn,Mn)Se QWs is studied by time-integrated and time-resolved pump-probe experiments respectively. Optical bistability is observed in ZnSe/ZnS SL embedded in Fabry-Perot cavities and attributed to an excitonic origin. Coherent exciton interactions lead to a blue shift of the exciton resonance as observed in coherent pump-probe experiments on ZnSe/(Zn,Mg)(S,Se) quantum wells. Time-resolved studies of the phonon-sideband emission in ZnSe/Zn(S,Se) and ZnSe/(Zn,Mg)(S,Se) MQWs directly reflect the relaxation dynamics of hot 1s(hh) excitons.