reference array item relative to selectiongrid button

I have a listof strings and a list of textures, both are added/remoted simultaniously, so each item in the list is assosiated with the other in the other string.

For example, my string list might be something like this: {"cube", "sphere", "cone"} while my texture array will be like this: {cubeTexture2D, sphereTexture2D, coneTexture2D}

as you can see, each one has a counterpart in the other list.

I have a selectiongrid that is based off of the texture array, so that it displays a button with each items texture. Here is the relevant code:

     public void AddedItem(string idRecieved){   //function to add items to the inventory, idRecieved is the ID string from our ItemPickup script    
     inventoryStrings.Add(idRecieved);
     inventoryButtons.Add(itemSelectedButton);
     itemSelected = playerCamera.GetComponent<ItemPickup>().itemHit;
     itemSelectedButton = itemSelected.GetComponent<itemIdentity>().identityButton;
     }
 
     void OnGUI(){
         int selectedButton = 0;
         if(isInventoryOpen)
         {
             Screen.lockCursor = false;
             selectedButton = GUILayout.SelectionGrid(selectedButton, inventoryButtons.ToArray(), 10, GUILayout.Height(50));
             Time.timeScale = 0;
             playerCamera.GetComponent<MouseLook>().enabled = false;
             GetComponent<MouseLook>().enabled = false;
         }
         else
         {
             Time.timeScale = 1;
             Screen.lockCursor = true;
             playerCamera.GetComponent<MouseLook>().enabled = true;
             GetComponent<MouseLook>().enabled = true;
         }
         
     }
     
 }

what I want, is in my void OnGUI, I want to have a variable that is equal to the string in the list that is assosiated with it's selectiongrid button. Since selectiongrid returns an int based on what button is selected, I was thinking to do something like:

 public string buttonReference;
 
 buttonReference = inventoryStrings.IndexOf(selectedButton);

But I dont think that will work.

tl;dr: I need to have buttonReference = the list item that is on the selectiongrid button the player presses.