I'm sure that Emmet Till was not the first, not by a longshot. But before him probably all the names of murdered black men killed by whites were either not recorded for history or else were slaves and thus their names were considered immaterial. Any record of the latter group would probably only have been recorded in business or property documents.

The picture in the middle lists names of black men killed by the Kansas City Police Department. The other two are from a KC protest (left) and on the right, names drawn in the street during the Minneapolis protests.