An attempt was made to arrange a marriage between him and his first cousin Isabella II of Spain which would end the Carlist conflict.

In 1855, Carlos Luis maintained contacts with his cousin Francisco de Asís to reach a reconciliation between the two Bourbon branches.

On 1 April, with a force of 4000 men, they landed on the Catalan coast at Sant Carles de la Ràpita.

After disembarking, they marched to Amposta to spend the night, but as they continued, the troops revolted, mistrusting the intentions of their commanders.

In spite of this, Carlos Luis' other brother and heir-presumptive Juan recognised the renunciations as valid and declared himself to be Carlist claimant to the throne.

In January 1861, within a space of less than two weeks, Carlos Luis, his wife Carolina, and his brother Fernando died, probably from typhus.