Titanium catecholate complexes can be desirable active materials for flow batteries and other electrochemical energy storage systems, particularly when incorporated in aqueous electrolyte solutions. It can be desirable to avoid introducing even traces of certain organic solvents into aqueous electrolyte solutions. Neat methods for synthesizing titanium catecholate complexes can help avoid the unwanted introduction of trace organic solvents into aqueous electrolyte solutions and also provide further advantages. Methods for synthesizing titanium catecholate complexes can include: combining a catechol compound and a titanium reagent in an absence of solvent to produce a reaction mixture, and reacting the titanium reagent with the catechol compound in a neat state to form a titanium catecholate complex containing at least one catecholate ligand. The titanium catecholate complex can be further reacted with a base to produce a salt form titanium catecholate complex, which can be present in an aqueous phase.