This paper suggests achieving diversity gains while utilizing low-denisty parity check (LDPC) codes in molecular communications. Intersymbol interference (ISI) causes a significant disadvantage in error performance for molecular communications. Even though decoding LDPC codes with soft decoding yields a considerable enhancement in the bit error rate (BER) curves, this can be further improved by utilizing diversity gain. In order to achieve this, two different messenger molecule types are sent to transmit the message codeword and its interleaved version. The molecular communication channel is then modeled, and the error performance of the proposed method is estimated by Monte-Carlo simulations. This approach provides considerable improvement in the error performance in the scenario where few messenger molecules are transmitted per bit.