Amir Khan says he will have no choice but to move up to welterweight if he successfully defends his WBA and IBF light-welterweight titles against Lamont Peterson.
Khan has been unable to secure bouts with WBO title holder Erik Morales or WBC champion Timothy Bradley.
"Maybe they're scared. I don't know," said the 25-year-old.
"There is unfinished business but I can't wait around because I've got other ambitions in my career."
The Bolton fighter added: "I want to unify the belts and become undisputed, unified light-welterweight champion.
"I've tried but they just won't take the fights. You can't force them. At the end of the day I'd like to fight them and prove I'm the best.
"I think that's the reason they've moved me to number one in the rankings, because they know that I'm the one who wants to fight but these guys don't want to face me."
A move to welterweight could see Khan meet the winner of a long-rumoured fight between WBO champion Manny Pacquiao and WBC belt holder Floyd Mayweather, which could finally happen next spring.
Prior to that, Shane Mosley, Victor Ortiz and Sheffield boxer Kell Brook may be targets for Khan.
"There are some real super-fights for me in that [welterweight] division that people will want to see," said the former Olympic silver medallist, who weighed in at 9st 13lbs for his fight with Peterson in Washington DC.
"There are big names in the welterweight division and I can work my way towards those big super-fights against the likes of Floyd Mayweather and also Shane Mosley, who is in that division and someone I could probably face.
"We've offered the fight to Mayweather's team and they are interested in the fight. I think that fight could happen in the next six to nine months, maybe even sooner. It depends how we come through this fight against Peterson.
"I want to take away that pound-for-pound world title from him and be known as the best fighter in the world. When the time is right, within the next six to nine months, we'll jump on that and take the fight against him."
Khan has stressed he will not underestimate his current challenger but Terry Edwards, Khan's cornerman when he won the silver medal at the 2004 Athens Olympics, believes Peterson will find it difficult against the Briton.
"[Peterson] has stopped almost 50% of his opponents, quite a few in the first round, so the early rounds could be difficult, but he's stepping up a league with Amir, who I think is at the top of his game," Edwards told BBC Radio 5 live.
Asked about Khan's ability to take a punch, Edwards, now Head of Boxing Operations for the London Olympics, said: "I think he's got a very strong chin. I was in Vegas when he boxed, [and beat, Marcos] Maidana and that was a coming of age for him - it dispelled all the hype about whether he's got a chin.
"With [Breidis] Prescott [when Khan lost in the first round] in the earlier days there was maybe a bit of complacency and I think he' learned from that and gone forward."
Peterson, who grew up in Washington, weighed in on the 140lbs limit for the fight that will take place in the early hours of Sunday morning UK time.
"If I want to match his hand speed then I will," said the American.
"If I don't, then there are other ways around it. If the fastest man always wins the fight then Muhammad Ali, Sugar Ray Leonard and fighters like that would have never lost. Roberto Duran wasn't the fastest guy but he beat Leonard. That's boxing.
"Speed is just one attribute. It means nothing to me. I'll do whatever I have to do to win."