[Ethereum] TypeError: Indexed expression has to be a type, mapping or array (is function (address) view external returns (string memory,string memory…)

I have 2 contracts first one is sub second one is main .
First i deploy main and create a new subtoken.
Then I want to access my maincontract in subToken contract but I cant 🙁
When I compile this contract I saw this error at getName2 function :

browser/opz4.sol:17:16: TypeError: Indexed expression has to be a type, mapping or array (is function (address) view external returns
(string memory,string memory,uint8,uint256,uint256)) return
mc.tokens[address(this)].name; ^——-^

pragma solidity ^0.5.0; 
import 'https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/math/SafeMath.sol'; 

contract SubToken{ 
    MainContract mc;

    constructor(address _address) public{  
       mc=MainContract(_address);

    }  

    function getName1() view public returns(string memory){
        return mc.getNameMain(address(this));
    }

    function getName2() view public returns(string memory){
        return mc.tokens[address(this)].name;
    }

    //function transferFrom(address from, address to, uint tokens) public returns (bool success); 
    //function allowance(address tokenOwner, address spender) public view returns (uint remaining);  
    //function transfer(address to, uint tokens) public returns (bool success) ;  
    //function approve(address spender, uint tokens) public returns (bool success);  
    //function transferFrom(address from, address to, uint tokens) public returns (bool success);  

    event Transfer(address indexed from, address indexed to, uint tokens); 
    event Approval(address indexed tokenOwner, address indexed spender, uint tokens); 

} 
contract MainContract {
    //mapping(address => mapping(address=>uint)) balances;

    //mapping(address => mapping(address => uint)) allowed;

    address[] public contracts;

    using SafeMath for uint;

    address contract_address;

    struct token{ 
        string  name; 
        string   symbol; 
        uint8  decimals; 
        uint  totalSupply; 
        uint balances;
    } 
    mapping(address => token) public tokens;

    address mycontraddress;

    function createNewContract(string memory _name,string memory _symbol,uint8 _decimals,uint256 _totalSupply,uint _balance) public returns(address youraddress){ 
        SubToken st = new SubToken(address(this));//address(this)
        tokens[address(st)] = token(_name,_symbol,_decimals,_totalSupply,_balance);
        mycontraddress=address(st);
        return mycontraddress;
    } 
    function seeContracttAddress() public view returns(address){
        return mycontraddress;
    }

    function getNameMain(address _address) public view returns(string memory){
        return tokens[_address].name;
    }

    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);

}

anyone can help me please 🙂