The　formation　of　thermodynamically　accessible　metallacycle　is　crucial　to　achieve　site-selective　C-H　bond　activation.　Here,　we　report　an　isocyanide-bridging　C-H　activation　through　the　formation　of　a　five　membered　palladacycle.　As　such,　a　proximal　C-H　bond　in　aldehyde　moiety　is　activated　selectively.　The　subsequent　palladium　shift　and　intramolecular　C=N　bond　insertion　construct　a　valuable　isoindolinone　framework.　Compared　with　conventional　isocyanide-promoted　C-H　bond　activation,　both　carbon　and　nitrogen　atoms　in　isocyanide　are　engaged　in　new　bond　formations.　Notably,　three　types　of　isoindolinones　can　be　obtained　selectively　by　variations　of　the　reaction　conditions.　Mechanistic　studies　shed　light　on　the　reaction　pathways.　Moreover,　the　synthetic　potential　of　current　methodology　is　demonstrated　by　providing　concise　routes　to　key　intermediates　of　indoprofen,　indobufen,　aristolactams,　lennoxamine,　and　falipamil.