Ther eview is aimeda tdescribingt he advances in electrophilic "iranium" ion-triggered Friedel-Crafts-type alkylation for polyenec yclizations. Owing to the greatp otential of halo-, seleno-and sulfeno-functionalized Friedel-Crafts alkylated compounds,n umerous catalytic methodsh aveb een developed in either racemico re nantiopure forms. More importantly,t hese arene-alkylated or polyenecyclized productsc ontaining halo,s eleno ands ulfeno functionality couldb eu seful in further synthetic planning to access biologically active molecules and natural productsw ith highly complex architectures. Starting from aw ide range of classicalL ewis acids, Brønsted acids and Lewis bases through to the very recently developed halogen bondc atalysts (XB-cat.), selenonium cations as Lewis acids etc. are utilized to access these types of compounds.M orer ecently, some of the co-operative catalytic systems such as phosphite-thiourea, sulfonic acid-phosphoramidite, sulfonic acid-selenophosphoramide,s ulfonic acidanion binding thiourea, etc. catalyzing highly diastereo-and enantioselective polyene cyclizations have also been described. Thec onfigurational stability,r eactivity and selectivity of three-membered cationic