Molecules that contain one or more unpaired electrons delocalized within a π-conjugated backbone are promising candidates for applications in spin electronics or simply 'spintronics'. Our group develops functional organic materials based on π-conjugated hydrocarbon molecules, where the electrons are unpaired either in the ground state or in the excited state that is low in energy and can be populated thermally. We aim to learn how to introduce and control a multitude of properties, namely, optical, chiroptical, magnetic, and conductive, in a bulk material made of these molecules, by manipulating spin interactions between the unpaired electrons. The first model system that was developed in our group is a hydrocarbon named cethrene, which has a diradicaloid singlet ground state and a low-lying triplet excited state. In this article, the structural parameters and their impact on the properties and reactivity of cethrene are discussed within the realm of the three C's that symbolize cethrene's C-shape, chirality, and chameleonic reactivity.