Critical and tricritical behavior of a selectively diluted triangular Ising antiferromagnet in a field

► We study selectively diluted triangular Ising antiferromagnet in a field. ► We apply an effective field theory with correlations that accounts for frustration. ► Ground-state configurations are examined for various field values. ► Determined phase diagrams for different parameters feature tricritical points. ► Presence of first-order phase transitions is confirmed by Monte Carlo simulation.