Organic Chemistry has always pondered these questions: What is this compound? How and why does it react? How can I make it? However, the way in which we answer these questions is continually changing with our increasing technological skills. We will build on the skills from ZPEM 2102 Organic Chemistry 2 in a course based on solving practical and theoretical problems. To answer these questions we will delve into spectroscopic problem solving, introduce molecular orbitals and use them to predict compound reactivity. Finally retrosynthetic analysis will be employed as a tool in developing synthetic pathways for a range of organic molecules.