Harnessing site selectivity in C-H functionalisation remains one of the greatest challenges in modern catalysis. In order to differentiate electronically and sterically similar C-H bonds, a variety of pioneering methods have been developed in recent years. One of the key developments is the use of Lewis basic directing groups to selectively direct a metal centre. The results herein report the manipulation of directing group chemistry to allow selective ortho, meta and para C-H functionalisation of arenes. Chapter 1 reports the developments in moving beyond ortho-selectivity in transition metal catalysed C-H functionalisation chemistry. Chapter 2 reports the use of the biologically relevant oxazolidinone and hydantoin heterocycles as weakly coordinating directing groups in ruthenium catalysed ortho-C-H alkenylation methodology. Chapter 3 reports the application of ruthenium catalysed σ-activation to the remote C-H functionalisation of indoles at the C6 position and carbazoles at the C4 position. Chapter 4 reports the manipulation of site selective cyclometalation and its application in the para-C-H alkylation of aniline derivatives.