Bonjour,
un début de piste,
Sub test()
Set sh1 = Sheets("Feuil1")
Set sh2 = Sheets("Feuil2")
LastRow = sh1.Cells(Rows.Count, "B").End(xlUp).Row
For i = 2 To LastRow
sNom = sh1.Cells(i, "B")
vDate = sh1.Cells(i, "C")
If Application.CountIf(sh2.Range("1:1"), sNom) = 0 Then
col = sh2.Cells(1, Columns.Count).End(xlToLeft).Column + 1
sh2.Cells(1, col) = sNom
sh2.Cells(2, col) = vDate
Else
col = Application.Match(sNom, sh2.Range("1:1"), 0)
lig = sh2.Cells(Rows.Count, col).End(xlUp).Row + 1
sh2.Cells(lig, col) = vDate
End If
Next
End Sub