In 2267, Krasnovsky's ship was put in at Starbase 11 when the USS Enterprise conducted its layover there. As a ranking officer, Krasnovsky served on the board conducting the court martial of a fellow captain, James T. Kirk, when Kirk was accused of the apparent death of Lieutenant Commander Benjamin Finney. (TOS: "Court Martial")
Captain Krasnovsky, played by actor Bart Conrad, wore a blue sciences division dress uniform, making him the highest-ranking officer to appear wearing science division dress colors, as admiral McCoy's uniform could be either sciences or command. All other science officers seen on Star Trek were commanders or below.
Krasnovsky was introduced as a "Star Captain." The only other starship commanders to wear a blue uniform were Lieutenant Commander Jadzia Dax after being placed in command of the USS Defiant in 2374 and Commander Spock in the alternate reality when he was placed in command of the USS Enterprise in 2258. Commander Branch commanded Epsilon IX station though the Station was an Outpost and not a Starship.