To probe how varying the electronic properties of the azophosphines would affect their overall structure and ligand ability, we targeted a series of azophosphines that varied at the N-aryl position. The para-substituent of the aryl group was changed from strongly electronic-donating to electron-withdrawing, while maintaining the same substituents on the phosphorus in all cases to enable simple comparison. Using our general synthetic route to azophosphines (1-R), via the corresponding azophosphine-borane (2-R), we obtained azophosphine-boranes 2-R (R = NMe2, OMe, Me, H, F, CF3) as brightly coloured red-orange solids (Scheme 1, isolated yields = 46-84%). The borane protecting groups in 2-R were removed to afford the corresponding azophosphines 1-R as darkercoloured solids or oils (isolated yields = 50-76%). Note that 1-NMe2 and 2-NMe2 were previously reported in our earlier communication, but all other molecules presented herein are novel. Scheme 1. Synthesis of azophosphines 1-R via the corresponding azophosphine-boranes 2-R.