Michael Yuchnitz, 60, was undergoing treatment for lung cancer at the time of his death but his lawyer, David Christian, said he didn't know if Yuchnitz's death Saturday was related to the illness.
No other information about the nature of Yuchnitz's death was reported.
Yuchnitz was scheduled to go on trial in March for allegedly trying to hire a hit man to kill his then-wife Tina Yuchnitz for $10,000, the San Antonio Express-News reported.
The owner of My Econo's $39.95 Optical stores was arrested in 2010 for solicitation of capital murder.
The couple underwent a high-profile divorce trial in which each side accused the other of abuse and bad behavior. A jury decided they had each inflicted emotional stress on the other and ordered their assets split 50-50, the newspaper said.
Yuchnitz was out on bail at the time of his death.