  Graphene with excellent 2D characters has been required to expand their
potentials for meeting applicational demands in recent years. As one avenue,
several approaches for fablicating 3D porous graphene network structures have
been developed to realize multi-functional graphene materials with 2D graphene.
Here we overview characteristics of 3D porous graphene for future electronic
device applications along with physical insights into "2D to 3D graphene",
where the characters of 2D graphene such as massless Dirac fermions are well
preserved. The present review thus summarizes recent 3D porous graphene studies
with a perspective for providing new and board graphene electronic device
applications.
