Herein,　two　types　of　tribocouple　pairs　based　on　polymer-like　carbon　(PLC)　films　are　designed　through　the　in　situ-formed　MXene　coating.　The　in　situ-formed　MXene　coatings　are　synthesized　via　the　in　situ　organic–inorganic　chemical　composite　technique-induced　anionic　polymers　with　different　molecular　weights　(≈450　000　and　≈4　000　000,　respectively).　Next,　the　tribotesting　condition　is　controlled　in　the　ambient　environment　under　different　loads　by　bare　and　PLC-coated　bearing　steel　balls　as　counterbodies.　During　the　whole　sliding　process,　a　lubricity　state　(friction　coefficient　is　about　0.21　and　wear　rate　is　about　1.5　×　10−6　mm3　N−1　m−1)　is　realized　on　the　self-mated　PLC　system.　Meanwhile,　the　contact　surfaces　are　covered　by　graphitic　2D　Ti3C2.　Compared　with　the　high-molecular-weight　modifier　system,　most　poly(acrylic　acid)-co-MXenes　grafted　by　the　low-molecular-weight　poly(acrylic　acid)　form　far　more　sp　2-C　phases.　Moreover,　active　groups　are　potentially　involved　in　forming　a　tribofilm,　which　enhances　the　overall　lubricity　of　MXenes　during　sliding.　This　verifies　the　key　to　achieving　low　friction　and　ultralow　wear　based　on　the　formation　of　the　nanostructured　sliding　interface　upon　MXenes　and　provides　an　expanded　application　of　solid　lubricants.　©　2022　Wiley-VCH　GmbH.