Bonjour,
Comme ceci:
Sub Lettre_Unique_en_Gras()
Dim i As Long, LastRow As Long
Dim ws As Worksheet
Set ws = Sheets("Base3")
LastRow = ws.Range("B" & Rows.Count).End(xlUp).Row
For i = 2 To LastRow
If Len(Cells(i, "B")) = 1 Then
Cells(i, "B").Font.Bold = True
Else
Cells(i, "B").Font.Bold = False
End If
Next i
End Sub
Cdlt