Defining Ranges

var workbook = new XLWorkbook();
var ws = workbook.Worksheets.Add("Defining a Range");

// With a string
var range1 = ws.Range("A1:B1");
range1.Cell(1, 1).Value = "ws.Range(\"A1:B1\").Merge()";
range1.Merge();

// With two XLAddresses
var range2 = ws.Range(ws.Cell(2, 1).Address, ws.Cell(2, 2).Address);
range2.Cell(1, 1).Value = "ws.Range(ws.Cell(2, 1).Address, ws.Cell(2, 2).Address).Merge()";
range2.Merge();

// With two strings
var range4 = ws.Range("A3", "B3");
range4.Cell(1, 1).Value = "ws.Range(\"A3\", \"B3\").Merge()";
range4.Merge();

// With 4 points
var range5 = ws.Range(4, 1, 4, 2);
range5.Cell(1, 1).Value = "ws.Range(4, 1, 4, 2).Merge()";
range5.Merge();

ws.Column("A").AdjustToContents();

workbook.SaveAs("DefiningRanges.xlsx");