Insurance records show that Molineux broke British trade laws in his business by sending ships to the Dutch Republic, so he might have been motivated to join the radical cause by increased customs duties and enforcement in the 1760s.
Molineux rose to prominence leading committees and crowds in demonstrations against the Townshend Acts, seizures by customs officers, and the stationing of British troops in Boston.
With Doctor Thomas Young he was one of the most radical among the genteel Whig organizers who sought to steer public demonstrations in Boston after 1765.
Friends of the royal government said he had committed suicide after being caught embezzling for the linen project from a New York merchant whose affairs he represented.
Because Molineux died before the American Revolutionary War began, and because some of his colleagues were uncomfortable with his radical methods, he was largely omitted in histories of America's independence.