The present invention generally provides compositions including carbon-containing molecules, and related methods. In some cases, the present invention relates to aromatic molecules comprising functional groups bonded to the aromatic portion of the molecule, including nonplanar portions of the molecules. Methods of the invention may provide the ability to introduce a wide range of functional groups to carbon-containing molecules. In some cases, methods of the invention may be performed using relatively mild reaction conditions, such as relatively low temperature, low pressure, and/or in the absence of strong acids or strong bases. The present invention may provide a facile and modular approach to synthesizing molecules that may be useful in various applications including photovoltaic devices, sensors, and electrodes (e.g., for electrocatalysis).