Summary: The primary goal of this study is to propose the concept of an operation \(\iota\) on \(\delta\)-preopen subsets in topological spaces. Here we defined the concepts of \(\iota\)-open sets, \(\iota\)-regular spaces and some topological properties such as \(\iota\)-closure, \(\iota\)-interior, closure\(_\iota\) of sub sets and \(\iota\)-derived were analysed. \(\iota-g\).closed sets and \(\iota-T_{1/2}\) spaces were studied. And a new set called \((\iota)\)-open sets are studied along with its properties.