Graphene, related two-dimensional crystals and hybrid systems showcase several key properties that can address emerging needs in electronics and optoelectronics, in particular for the ever growing markets of printed, flexible and wearable electronic devices. Graphene's flexibility, large surface area, and chemical stability, combined with its excellent electrical and thermal conductivity, make it promising as a printed flexible electrodes in flexible and wearable electronic devices. Chemically functionalized graphene and self -assembly of graphene-organic molecule composites can also improve mobility and conductivity of organic semiconducting thin film transistors (ITT). Two-dimensional crystals and hybrid systems provide optical and electrical properties complementary to those of graphene, enabling the realization of printed an flexible ultrathin-film photodetectors or photovoltaic systems. Here, we review the use of graphene and related materials for printed and wearable electronics and optoelectronics, defining the roadmap for future applications in this area. (C) 2018 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license.