The present invention is generally directed to methods of making diester-based (bio)lubricant compositions, wherein such diester-based lubricant compositions generally comprise diester species prepared by reacting vicinal diol species with monoester(s) of one or more fatty acids. In some embodiments, such methods for making such diester-based lubricants utilize one or more biomass precursor species (e.g., monoesters of fatty acids derived from crop oils and/or other source of triglyceride species such as algae). In some embodiments, such diester-based lubricants are derived from Fischer-Tropsch (FT) olefins, typically alpha (α)-olefins.