Carbonaceous　materials　(CMs),　such　as　carbon　nanotubes,　fullerenes,　graphene,　carbon　quantum　dots,　graphdiyne,　and　their　derivatives,　have　sparked　enormous　excitement　because　of　their　attractive　properties　and　great　potential　for　solar　energy　conversion　applications.　Although　pristine　CMs　are　known　for　their　unique　electronic　structure,　optical　properties,　and　thermal　conductivity,　many　research　fields　and　applications　require　functionalized　CMs　with　integrated　physicochemical　properties　and　tunable　dimensionality.　Structurally　modifying　CMs　through　various　surface/interface　engineering　reveals　the　numerous　possibilities　for　tuning　their　architectures　and　properties.　This　Review　mainly　focuses　on　the　basic　surface/interface　engineering　issues　of　diverse　CMs.　The　effects　of　surface/interfacial　engineering　in　versatile　systems　as　well　as　the　excellent　mechanical,　electronic,　optical　properties　and　applications　of　the　functionalized　CMs-based　composites　are　highlighted.　Some　ongoing　challenges　and　possible　solutions　for　future　exploration　of　CMs-based　functional　composites　are　critically　discussed.　©　2020　WILEY-VCH　Verlag　GmbH　&　Co.　KGaA,　Weinheim