Selective reductive elimination of ethane (Csp(3)-Csp(3) RE) was observed following bromide abstraction and subsequent thermolysis of a Pt(IV) complex bearing both Csp(3)- and Csp(2)-hybridized hydrocarbyl ligands. Through a comparative experimental and theoretical study with two other Pt(IV) complexes featuring greater conformational flexibility of the ligand scaffold, we show that the rigidity of a meridionally coordinating ligand raises the barrier for Csp(2)-Csp(3) RE, resulting in unprecedented reactivity.