In this study, we propose a microeconomics model to verify the effects of the non-cash collateralization on the liquidity of the over-the-counter (OTC) derivatives markets accepting both cash and non-cash assets. Liquidity in this study is measured as an equilibrium volume of the derivatives contract. The equilibrium volume is obtained by solving the utility maximization problem of a risk-averse collateral payer who wants to optimize her/his capital. The collateral payer's capital depends on the non-cash asset used as collateral. We consider both option and forward contracts as example. Our sensitivity analysis shows that the optimal combination of cash and non-cash collaterals can maximize the liquidity of derivatives. Especially, for option contracts, the market requires both cash and non-cash collaterals for liquidity. Overall, the introduction of non-cash collateralization boosts the liquidity of derivatives contracts. We also show how the arrangements of collateralization can boost the liquidity of the OTC derivatives markets. Moreover, we demonstrate that the combination of cash and non-cash collaterals to maximize liquidity differs from that to maximize the participant's utility. This indicates that the optimal combination is not efficient in terms of Pareto criteria.