Following the popularity and hype around graphene, researchers started to study other 2D materials, and Molybdenum Disulfide (MoS2) is one of the most promising of those "new" 2D materials.
Molybdenite is a natrual ore that is similar to graphite, and is built from 2D MoS2 sheets. MoS2 can be obtained rather easily from Molybdenite.
Similarly to graphene, MoS2 has excellent electronic and optical properties. However, unlike graphene, MoS2 has a 1.8 eV bandgap - which means that MoS2 is suitable as a material for transistors and photodetectors. MoS2 is strong, conductive and can emit and absorb light and is so considered a promising 2D material for some applications for which graphene is not suitable.