Abstract: van der Waals heterostructure devices, composed from the assembly of 2D crystals, could enable new spintronics functionalities that are not accessible in individual crystals or any other bulk materials . In this talk, I will present our spin dependent electronic transport measurements in such ultra-thin devices. Firstly, I will demonstrate that by bringing semi-metallic graphene into a proximity to transition metal dichalcogenides, we enhance its weak spin orbit coupling strength three orders of magnitude  and simultaneously realize optospintronics functionality . Then, I will show that semiconducting black phosphorus-based van der Waals heterostructures exhibit remarkable spin transport properties after an in-situ h-BN encapsulation process . Finally, I will provide an outlook about 2D van der Waals spin devices after briefly reviewing recently discovered 2D magnets . Novoselov, K. S., Mishchenko, A., Carvalho, A. & Neto, A. H. C. 2D materials and van der Waals heterostructures. Science 353, aac9439 (2016). Avsar, A. et al. Spinorbit proximity effect in graphene. Nature Communications 5, 4875 (2014). Avsar, A. et al. Optospintronics in Graphene via Proximity Coupling. ACS Nano 11, 1167811686 (2017). Avsar, A. et al. Gate-tunable black phosphorus spin valve with nanosecond spin lifetimes. Nature Physics 13, 888893 (2017). Avsar, A. et al. van der Waals Bonded Co/h-BN Contacts to Ultrathin Black Phosphorus Devices. Nano Lett. 17, 53615367 (2017).6. Burch, K. S., Mandrus, D. & Park, J.-G. Magnetism in two-dimensional van der Waals materials. Nature 563, 47 (2018).