Use of Model and View (MVC)
You can for sure replace this loop by using Select()  

public ActionResult Index()
{
    IEnumerable&lt;MaterialRequestModel&gt; model= DB.MaterialRequest
        .Where(m =&gt; m.MaterialStatusId == MatStatus.A9Cancelled || m.MaterialStatusId == MatStatus.A8Complete)
        .Select(r =&gt; new MaterialRequestModel(r, DB.Employees.Find(r.ConcernedEmployeeId), DB.Employees.Find(r.OrderedByEmployeeId), DB.Offices.Find(r.OfficeId)));
    return View(query.ToList());
}  


or much cleaner by a separate method  

public ActionResult Index()
{
    IEnumerable&lt;MaterialRequestModel&gt; model= DB.MaterialRequest
        .Where(m =&gt; m.MaterialStatusId == MatStatus.A9Cancelled || m.MaterialStatusId == MatStatus.A8Complete)
        .Select(r =&gt; CreateMaterialRequestModel(r));
    return View(query.ToList());
}  

private MaterialRequestModel CreateMaterialRequestModel(MaterialRequest materialRequest)
{
    return new MaterialRequestModel(r, DB.Employees.Find(r.ConcernedEmployeeId), DB.Employees.Find(r.OrderedByEmployeeId), DB.Offices.Find(r.OfficeId));
}  


which can be improved further by caching the employee and office in a dictionary.  

private Dictionary&lt;int, Employee&gt; cachedEmployees = Dictionary&lt;int, Employee&gt;();
private Employee GetEmployeeById(Int id)
{
    Employee employee;
    if cachedEmployees.TryGetValue(id, out employee)
    {
        return employee;
    }
    employee = DB.Employees.Find(id);
    if(employee != null)
    {
        cachedEmployees[id] = employee;
    }
    return employee;
}  


in the same way the office cacheing can be done, which results CreateMaterialRequestModel()  

private MaterialRequestModel CreateMaterialRequestModel(MaterialRequest materialRequest)
{
    return new MaterialRequestModel(r, GetEmployeeById(r.ConcernedEmployeeId), GetEmployeeById(r.OrderedByEmployeeId), GetOfficeById(r.OfficeId));
}  


there is only a small problem. Any changes to an employee or an office won't be reflected in the dictionaries.